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1
Ma, Liang. "Genetic studies for aquaculture and stock-enhancement of red drum (Sciaenops ocellatus)." Texas A&M University, 2003. http://hdl.handle.net/1969.1/6012.
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Hypervariable, nuclear-encoded microsatellites were used to (i) estimate genetic
effective size (Ne) of red drum spawning over a two-week period in nine brood tanks at a
TPWD hatchery; (ii) estimate heritability of early-larval growth and of growth rate and
cold tolerance of juveniles; and (iii) test Mendelian segregation and independent
assortment of 31 nuclear-encoded microsatellites. Assuming all tanks contributed
equally to an offspring population, the maximum (expected) and observed Ne over the
nine brood tanks was 43.2 and 27.0, respectively. The estimate of Ne based on
observed variation in family size was 19.4. Simulations indicated that over a limited
time period the simplest approach to maximizing Ne for a release population would be to
utilize equal numbers of progeny from each brood tank. A family (genetic) effect was
found to contribute significantly to the variance in early larval growth, juvenile growth
rate, and cold tolerance. Estimates of narrow-sense heritability for these three traits
were 0.07 +- 0.03, 0.52 +- 0.21 and 0.20 +- 0.10 (two growth intervals measured), and 0.30 +- 0.11, respectively, under the genetic models employed. The relatively low estimate
of heritability for early larval growth suggests that genetic improvement for this trait
likely would be slow. The heritability estimates for juvenile growth rate and cold
tolerance, alternatively, suggest that genetic selection for these traits could be effective. Segregation at all 31 microsatellites fit Mendelian expectations for autosomal loci; a null
allele was inferred at two of the microsatellites. Results from pairwise tests of
independent assortment demonstrated that 20 of the 31 microsatellites could be placed
into seven linkage groups. Additional linkage groups inferred from a prior study
increased the number of inferred linkage groups in red drum to nine, with a range of two - five (avg. = 2.78) microsatellites in each linkage group. The remaining 11
microsatellites tested in this study assorted independently from all other microsatellites,
suggesting the possibility of 11 additional linkage groups.
2
Trzaskowski, Maclej. "Heritability and missing heritability : can twin studies be trusted?" Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/heritability-and-missing-heritability(e8934ae4-4be3-4179-8fb6-31700968f1a2).html.
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'Missing heritability' is the discrepancy between the amount of variance explained by specific single nucleotide polymorphisms (SNPs) identified in genome-wide association (GWA) and twin-estimated heritability. Four categories of explanations have been proposed for missing heritability: (1) additive effect sizes of common single nucleotide polymorphisms (SNPs) used in GWAS are too small to detect with current sample sizes; (2) rare variants are not captured by commercial arrays; (3) nonadditive effects (allelic, gene-gene or gene-environment interactions); (4) twin estimates of heritability are inflated. A recently developed quantitative method that uses GWA data- Genome-wide Complex Trait Analysis (GCTA)- has made it possible to explore these issues as it allows to compare quantitative twin-based estimates with quantitative DNA-based estimates. I use data from an on-going longitudinal study of 14,000 twins (7000 pairs) born in the UK between 1994 and 1996 called the Twins Early Development Study (TEDS) to investigate the following: the proportion of twin heritability that can be explained by additive effects of common SNPs (Chapters 2, 3 and 4); increasing heritability across development in the presence of strong genetic stability (Chapters 5 and 6); and genetic pleiotropy (Chapter 7). In Chapters 2, 3 and 4, Iapply univariate twin, GWA and GCTA methods to demonstrate that although we are still far from closing the gap between heritability and the actual genetic variants, there still is scope for discovery of common additive genetic effects. In Chapters 5, 6 and 7, I employ bivariate GCTA, polygenic predictor scores (PGS) and twin estimates from the same sample to confirm that twin estimates and DNA estimates of genetic pleiotropy and stability concur. In conclusion, in this thesis I provide evidence that much of the so-called 'missing heritability' can be explained by common additive genetic effects and that phenomena from twin research can be replicated using DNA alone.
3
Meehan, Anna, and Henrik Evertsson. "Genetic and Environmental Influences on Psychopathic Personality Traits : A Meta-Analytic Review." Thesis, Örebro universitet, Institutionen för juridik, psykologi och socialt arbete, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-27685.
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To understand the etiology of psychopathic personality traits and thus in the long run to be able to develop successful prevention, a first step is to find out what role genetic and environmental effects play. A meta-review of 15 twin studies (N=26, 981), was conducted to estimate the magnitude of genetic and environmental influences on psychopathic personality traits. The results show that additive genetic (heritable) factors and non-shared environmental factors each explain 50% of the variance in psychopathic personality traits, while shared environmental factors were of no importance. Measure, informant, age, and sex were investigated as potential moderators showing that informant had an impact on the findings. This meta-analysis provides a structured synthesis of the relative genetic and environmental contributions in psychopathic personality traits through various stages of development and across sex.För att förstå etiologin av psykopatiska personlighetsdrag och därmed i det långa loppet kunna utveckla framgångsrik prevention, är ett första steg att klargöra vilken roll genetiska och miljömässiga effekter spelar. En meta-översikt på 15 tvillingstudier (N=26,981), genomfördes för att uppskatta i vilken grad genetiska och miljömässiga faktorer påverkar psykopatiska personlighetsdrag. Resultaten visade att additiva genetiska (ärftliga) och unika miljömässiga faktorer förklarar 50% var av variansen i psykopatiska personlighetsdrag, medan delade miljömässiga faktorer inte var av betydelse. Mått, informant, ålder och kön undersöktes som potentiella moderatorer och visade att informant påverkade resultaten. Denna meta-analys ger en strukturerad syntes av de relativa genetiska och miljömässiga bidrag som påverkar psykopatiska personlighetsdrag genom olika utvecklingsstadier och mellan könen.
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Langstaff, Helen Katherine. "The heritability of facial morphology." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25447.
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Facial recognition methodologies, widely used today in everything from automatic passport controls at airports to unlocking devices on mobile phones, has developed greatly in recent years. The methodologies vary from feature based landmark comparisons in 2D and 3D, utilising Principal Component Analysis (PCA) to surface-based Iterative Closest Point Algorithm (ICP) analysis and a wide variety of techniques in between. The aim of all facial recognition software (FCS) is to find or match a target face with a reference face of a known individual from an existing database. FCS, however, faces many challenges including temporal variations due to development/ageing and variations in facial expression. To determine any quantifiable heritability of facial morphology using this resource, one has to look for faces with enough demonstrable similarities to predict a possible genetic link, instead of the ordinary matching of the same individual’s face in different instances. With the exception of identical twins, this means the introduction of many more variables into the equation of how to relate faces to each other. Variation due to both developmental and degenerative aging becomes a much greater issue than in previous matching situations, especially when comparing parents with children. Additionally, sexual dimorphism is encountered with cross gender relationships, for example, between mothers and sons. Non-inherited variables are also encountered such as BMI, facial disfigurement and the effects of dental work and tooth loss. For this study a Trimmed Iterative Closest Point Algorithm (TrICP) was applied to three-dimensional surfaces scans, created using a white light scanner and Flexscan 3D, of the faces of 41 families consisting of 139 individuals. The TrICP algorithm produced 7176 Mesh-to-mesh Values (MMV) for each of seven sections of the face (Whole face, Eyes, Nose, Mouth, Eyes-Nose, Eyes-Nose-Mouth, and Eyes-Nose- Mouth-Chin). Receiver Operated Characteristic (ROC) analysis was then conducted for each of the seven sections of the face within 11 predetermined categories of relationship, in order to assess the utility of the method for predicting familial relationships (sensitivity/specificity). Additionally, the MMVs of three single features, (eyes, nose and mouth) were combined to form four combination areas which were analysed within the same 11 relationship categories. Overall the relationship between sisters showed the most similarity across all areas of the face with the clear exception of the mouth. Where female to female comparison was conducted the mouth consistently negatively affected the results. The father-daughter relationship showed the least similarity overall and was only significant for three of the 11 portions of the face. In general, the combination of three single features achieved greater accuracy as shown by Areas Under the Curve (AUC) than all other portions of the face and single features were less predictive than the face as a whole.
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Thomas, Stuart C. "Estimation of heritability using inferred relationships." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/11464.
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Two existing estimators use inferred relationship information on a pair-wise level: regression of the phenotypic similarity of a pair of individuals on an estimate of their relationship and a likelihood procedure that maximises the probability of their genotypic and phenotypic observations. Computer simulation was used to compare the behaviour of these approaches. Bias in estimates of heritability decreased with increasing sample size, decreased heritability, increasing relatedness and increasing sample size. The regression approach showed less bias than the likelihood approach, but much larger sampling variance. A modified form of the likelihood technique, requiring fewer initial assumptions about population parameters was developed, which showed lower bias in its estimates of heritability than the likelihood technique originally proposed. An alternative approach in which marker-information was used to reconstruct sibships through relationship assignment within a single generation using Markov chain Monte Carlo (MCMC) techniques was developed. The reconstructed sibships were assumed correct and analysed using restricted maximum likelihood under an animal model. Simulations to compare the properties of estimates with those made using existing techniques indicated that sibship reconstruction was, in many cases, superior to earlier methods, regaining family-specific weighting lost through pair-wise analysis, having lower mean squared errors and showing only slight downwards bias, provided that there was sufficient marker information. Equations appropriate for MCMC analysis of half-sib, full-sib and hierarchical sib-ship structures are presented. The approaches were extended so that information from other types of marker loci, for example mitochondrial or dominant loci, known maternal information and additional variance parameters can be incorporated into the analysis. Analysis using the technique was made of feral population of Soay sheep, with body weight being used as an example trait. Results indicated that the Soay population has a low level of relatedness and so heritability estimates were not reliable, unless inferred relationship data was used only to augment an existing set of known relationships.
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Carper, Benjamin Alan. "Assessing Multivariate Heritability through Nonparametric Methods." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2565.pdf.
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Graham, Nicholas Dale. "The Heritability of Refractive Error between Siblings." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275350173.
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Vu, Alexander. "Sluggish Cognitve Tempo: Stability, Validity, and Heritability." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1446570242.
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Hodcroft, Emma B. "Estimating the heritability of virulence in HIV." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15814.
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The rate that HIV-infected individuals progress to AIDS and death varies greatly. Viral load taken during the asymptomatic phase of the disease is one of the best-known predictors of HIV progression rate and transmission risk, and is known to be in uenced by both host and environmental factors. However, the role that the virus itself plays in determining the viral load is less clear. Previous studies have attempted to quantify the amount the viral genome in uences viral load, or the heritability of viral load, using transmission pairs and phylogenetic signal in small sample sizes, but have produced highly disparate estimates. E cient and accurate methods to estimate heritability have been utilised by quantitative geneticists for years, but are rarely applied to non-pedigree data. Here, I present a novel application of a population-scale method based in quantitative genetics to estimate the heritability of viral load in HIV using a viral phylogeny. This new phylogenetic method allows the inclusion of more samples than ever previously used, and avoids confounding e ects associated with transmission pair studies. This new method was applied to the two largest HIV subtypes found in the UK, subtypes B and C, using sequences and clinical data from UK-wide HIV databases. For subtype B (n=8,483) and C (n=1,821), I estimated that 5.7% (CI 2.8{8.6%) and 29.7% (CI 14.8{44.7%) of the variance in viral load is determined by the viral genome, respectively. These estimates suggest that viral in uence on viral load varies greatly between subtypes, with subtype C having much larger viral control over viral load than subtype B. I expanded the phylogenetic method to test whether the component of the viral load determined by the virus has changed over time. In subtype B, I foundevidence of a small but signi cant decrease in the viral component of viral load of -0.05 log10 copies/mL/yr. I built a stochastic, individual-based model capable of simulating a realistic HIV epidemic, with heritable viral loads that in uence transmission and disease progression, capable of generating data sets to assess the accuracy of phylogenetic methods. This was successfully used to generate epidemics approximating those in a small African village and a Western `men who have sex with men' community under a variety of conditions. To test the accuracy of the new phylogenetic heritability estimation method, simulated datasets were generated with the heritability of viral load set at values of 30%, 50%, 70%, and 90%. Unfortunately, complications in the heritability equation used prevented full assessment of the new phylogenetic method on the simulated data. Future development of the model will enable simulation of realistic viral loads under varying heritability values, enabling simulation of data sets that can be used to test this and other heritability estimation methods. This new phylogenetic method allows accurate estimation of heritability in large datasets, and has provided valuable insight into the viral in uence on viral load in HIV.
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Spooner, Simon K. "Predictors of hallux valgus : a study of heritability." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/8784.
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Hallux valgus is a complex progressive foot deformity of uncertain aetiology. The disorder is characterised by a lateral deviation of the hallux at the first metatarsophalangeal joint; an angle ≥ 15° is considered as clinical hallux valgus. A model that predicts first metatarsophalangeal joint angle and thus, hallux valgus is potentially very useful; enabling the clinician to identify individuals at risk of developing the disorder and to predict prognosis. The aim of this study is to develop such a model. The literature relating to hallux valgus identifies eight potential aetiological factors of hallux valgus. The scientific evidence presented in support of these suspected aetiological factors, and the theories of pathology of hallux valgus in association with these factors were critically evaluated by a review of the literature. Methods to evaluate the significance of these factors in hallux valgus were identified and appraised. These methods were applied to a large sample of genetically related individuals. The genetic and environmental influences affecting first metatarsophalangeal joint angle, pes planus, metatarsal formula, digital formula and first ray neutral position were explored through the statistical analysis of the data obtained from the sample. The results of analyses suggest that all of these variables are gender influenced, multifactorial traits. Further analysis of a subset of data generated a statistical model that relates the degree of hallux deviation at the fast metatarsophalangeal joint (and thus, the degree of hallux valgus) to clinically measurable predictor variables. A further subset of data was applied to test the model. The model was found to accurately predict first metatarsophalangeal joint angle in 92% of cases. Application of the model allows the clinician to evaluate an individual's risk of developing hallux valgus enabling accurate prognosis. Recommendations for achieving improved prognosis and the implications for future research are proposed.
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Meacham, Nancy S. "Heritability estimates for calving date in Simmental cattle." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45782.
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Variation among sires in daughters' reproductive performance was analyzed using data on 4,360 cows from nine herds obtained from the American Simmental Association. Cows were required to have at least 50% Simmental breeding, to have calved first at 2 yr of age and to have been born and subsequently calved in the same herd and season. Traits analyzed included first and second calving dates, first calving interval and the percentage of cows that returned to calve in the same season as 3-yr-olds. Data were adjusted for effects of percentage Simmental and first-calf calving ease score.
At second calving, purebred Simmentals calved 1.7 ± 1.2 d later than 75% Simmental cattle and 5.1 ± 1.4 d later than 50% Simmental cattle. When compared to cows that calved without assistance at first calving, cows experiencing easy pulls were 1.7 ± 1.4% less likely to calve as 3-yr-olds and had 4.9 ± 1.0 d longer calving intervals. Cows with hard pulls were 9.0 ± 2.1% less likely to return and had 6.5 ± 1.6 d longer calving intervals. Cows requiring Cesarean section were 23.1± 2.5% less likely to return and had 19.6 ± 2.4 d longer calving intervals. Heritability estimates were .17 ± .04 for first calving date, .07 ± .06 for second calving date, .04:105 for calving interval and .11 ± .04 for percent return. Calving interval does not appear to be a useful selection criterion to improve reproduction. Phenotypic and genetic correlations of first calving date with calving interval were -.58 and -.83 ± .37, respectively. The genetic correlation between first and second calving dates was .66 ± .41. Given current data recording procedures, calving date appears to be the most useful potential selection criterion to improve reproductive fitness.Master of Science
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Hartmann, Katherine Louise Seal Hartmann. "Addressing the Missing Heritability of Coronary Artery Disease." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471544354.
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Zhang, Xueyi Zhang. "Enrichment of Heritability Across Several Hypertension Related Traits." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case152301297309475.
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Rastogi, Amal. "Heritability of Autoantibody Levels in a Twin Population." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1854.
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AIM: This study aims to determine what portion of specific autoantibody phenotypes are genetically determined by using a twin model. METHODS: This study specifically examines Anti-Ro(SSA), Anti-La (SSB), Anti-Sn/RNP, Anti-Sm, Anti-Jo-1, Anti-Scl-70, Anti-Tg & Anti-TPO, Anti-dsDNA, Anti-PS, and Anti-cardiolipin antibodies for their heritability. This study examined 104 same-sex adult twins (66 monozygous, 38 dizygous) for the above mentioned autoantibody values. The serum autoantibody values in each subject were quantified using automated ELISA. Descriptive statistics including, distributions, quantiles, and moments were calculated by zygosity for continuous antibody values, subject ages, gender, race and smoking status. Categorical antibody levels were used to determine twin pair concordance rates. Continuous and rank ordered autoantibody values were used to determine the presence and portion of a genetic component. To evaluate how strongly the antibody values in each twin group resembled each other, the intraclass correlation was calculated for each antibody by zygosity. The genetic variances, environmental variances, and heritability were estimated using path models with maximum likelihood estimation techniques. The phenotypic variance was modeled as a linear function of underlying additive genetic (A), dominant genetic (D), common environmental (C), and random environmental (E) effects. RESULTS: Several antibodies demonstrated a genetic component in our study population. Anti-cardiolipin had a genetic component with an estimated 69% heritability. Anti-dsDNA yielded a genetic component with a heritability estimate of 55-62%. Anti-Jo-1 presented a genetic component with the heritability estimate to be 41-51%. Anti-SCL-70 demonstrated a genetic component with a heritability estimate of 42-59%. Anti-PL had a genetic component with a heritability estimate of 52-54%. Several antibodies did not have a measurable genetic component. These included anti-Sm, anti-Ro(SSA), anti-La(SSB), anti-sn/RNP, anti-Tg, and anti-TPO. Some possibilities for the lack of a measureable genetic component may be due to the limited number of discordant twin pairs and/or the small number of subjects with higher levels of antibodies. CONCLUSION: The results of this study suggest several clinically relevant markers of auto-immunity may be partially genetically determined. These include: anti-cardiolipin, anti-dsDNA, anti-Jo-1, anti-SCL-70, and anti-phospholid.
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Keller, Margaux Finn. "HERITABILITY AND SEX-EFFECT ANALYSES OF NEURODEGENERATIVE DISEASE." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/288134.
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AnthropologyPh.D.
This work analyzes the genetic basis of three neurodegenerative diseases using several thousands of individuals of European descent to determine a range of phenotypic heritability outside of what has been identified by prior methods. By measuring additive genetic variance genome-wide, measures of its contribution to the phenotypic variance of these diseases were substantially increased, in some instances by a factor of 10 or more. Additionally, regional-mapping methods identified segments of the genome exhibiting significantly high heritability estimates associated with one of the neurodegenerative diseases, Amyotrophic lateral sclerosis. This resulted in the detection of novel candidate regions and provided conclusive evidence for the polygenic architecture of this disease. Lastly, novel risk variants associated with Parkinson's disease were identified on the X chromosome, a previously ignored genomic region. Overall, the employment of new analytic methods produced robust and novel results, adding substantial information to the neurodegenerative disease literature and connecting the anthropological perspective with growing informatics-based methods.
Temple University--Theses
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Bellera, Carine. "Detecting heritability of brain structure using magnetic resonance imaging." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31194.
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A method is described that allows one to assess heritability of brain structures using magnetic resonance images (MRI). We have obtained MRI images for a group of identical twins and another group of fraternal twins. Each MRI image was segmented into white and gray matter then smoothed to estimate white and gray matter density at each 3D image element or voxel. At each voxel, we use the intraclass correlations of the two groups in order to compute a 3D image of a measure of heritability, as well as a test statistic for detecting those regions with significant heritability. To our knowledge the genetic variability of white and gray matter density has not been investigated on a voxel basis previously.
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Song, Jiming. "Estimation of heritability of feed intake in Canadian Holsteins." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86977.
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A total of 95,678,311 feed records from January 2000 to May 2007, corresponding to 16,866,117 test-day records or 1,714,651 cow lactation records obtained from Quebec Dairy Herd Improvement program, VALACTA were used to estimate heritabilities of feed intake. Genetic parameters of feed intake were estimated using both a single and two-trait (with milk yield as the second trait) animal models which included herd-year-season (hys) at calving, age at calving, male and female phantom groups as fixed effects, and animal and residual as random effects (i.e. for analysis of complete lactation feed intake in parity 1, there were 119,620 cows from 1,248 sires and 88,500 dams, 20,133 levels of hys, 20 levels of age at calving and 49 phantom groups). The model was fitted by Restricted Maximum Likelihood and relationships among animals were taken into account on both the male and female side of the pedigree (i.e. for analysis of complete lactation feed intake in parity 1, there were 308,029 animals from 6 generations in the pedigree file). Heritability estimates obtained from the single trait model ranged from 0.04 to 0.14 for complete lactation feed intake traits, 0.01 to 0.03 for 90-d feed intake traits, 0.08 to 0.19 for 305-d feed intake traits, and 0.10 to 0.21 for daily feed intake traits. Heritability estimates for 305-d dry matter intake obtained from the two-trait model were 0.06, 0.01 and 0.08 in parity 1, 2 and 3 respectively.Un total de 95 678 311 relevés de consommation de nourriture récoltés entre janvier 2000 et mai 2007, correspondant à 16 866 117 relevés Jour de Test ou à 1 714 651 relevés de lactation de vaches, ont été obtenus grâce au programme d'analyse des troupeaux laitiers du Québec, VALACTA, et été utilisés afin d'estimer l'héritabilité de la consommation. Les paramètres génétiques de consommation ont été établis en utilisant des modèles d'animaux à un ou deux caractères. Bien que le second caractère était toujours la production de lait, les autres caractères utilisés incluaient des effets fixes tels que des effets troupeau-année-saison au vêlage, âge au vêlage, les groupes d'ascendance paternelle et maternelle, ainsi que des effets aléatoires tels qu'animal et résiduels. Par exemple, pour l'analyse de la comsommation complète pendant la lactation de la parité 1: il y avait 119 620 vaches issues de 1 248 taureaux et 88 500 vaches, 20 133 niveaux de troupeau-année-saison, 20 niveaux d'âge au moment d u vêlage, et 49 groupes d'ascendance paternelle et maternelle. Les modèles ont été formatés selon une méthode de vraisemblance maximale restreinte (REML) et en prenant en compte les liens génétiques entre animaux, lesquels ont été inclus dans les pedigrées des males et des femelles. Ainsi, pour l'analyse de la comsommation complète pendant la lactation de la parité 1, il y avait 308 029 animaux de 6 générations dans le fichier pedigrée. Les estimations de l' héritabilité obtenues à l'issu du modèle à un caractère variaient de 0.04 à 0.14 pour la consommation complète pendant la lactation, de 0.01 à 0.03 pour les caratères obtenus suite à une consommation sur 90 jours, de 0.08 a 0.19 suite à une consommation de 305 jours, et de 0.10 à 0.21 pour les caractères de consommation journalière. L'héritabilité estimée depuis le modèle à deux caratères et suite à 305 jours de consommation de matière sèche é
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Araujo, Marcelo Renato Alves de. "Variation and heritability in meadow bromegrass (Bromus riparius Rehm.)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63859.pdf.
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Bismark, Andrew W. "The Heritability Of And Genetic Contributions To, Frontal Electroencephalography." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/332852.
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The heritability of frontal EEG asymmetry, a potential endophenotype for depression, was investigated using a large set of adolescent and young adult twins. Additionally, the relationship between polymorphisms within three serotonin genes, two receptor genes and one transporter gene, and frontal EEG asymmetry was also investigated. Using Falconer's estimate, frontal EEG asymmetry was shown to be more heritable at lateral compared to medial cites across nearly all reference montages, and greater in males compared to females. Using structural equation modeling (SEM), and investigating both additive (ACE) and non-additive (ADE) models of genetic heritability, males displayed consistently greater additive genetic contributions to heritability, with greater lateral contributions than medial ones. For female twins pairs, the additive genetic model data provided a mixed picture, with more consistent heritability estimates observed at medial sites, but with larger estimates shown at lateral channels. For non-additive genetic models, male twin pairs demonstrated exclusive non-additive contributions to heritability across channels within AVG and CZ referenced data, with metrics in the CSD and LM montages more mixed between additive and non-additive contributions. However, consistent with Falconer's estimates, lateral channels were nearly always estimated to be more heritable than medial channels regardless of gender. These models demonstrate some combination of additive and non-additive contributions to the heritability of frontal EEG asymmetry, with the CSD and AVG montages showing greater lateral compared to medial heritability and CZ and LM montages showing mixed contributions with additive heritability at lateral channels and non-additive primarily at medial channels. The complex interaction of gender and reference montage on the heritability estimates highlight the subtle yet important roles of age, gender, and recording methodology when investigating proposed endophenotypes. However, no association was found between the proposed polymorphisms in serotonin receptor 1a, 2a or serotonin transporter genes and frontal EEG asymmetry. Although the results support modest heritability of frontal EEG asymmetry, the proposed link to underlying serotonergic genetic markers remains an open question. Overall, these results indicate that frontal asymmetry may be a useful endophenotype for depressive risk with modest heritability, but is one that taps more environmental risk.
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Carroll, Will. "Maternal versus paternal factors in the heritability of asthma." Thesis, Keele University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487303.
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Asthma is a complex disorder with environmental and genetic triggers. These have been the subject of extensive study but progress in establishing reliable genetic determinants of this disease have met with only limited success. In this thesis I report on how the asthma phenotype in childhood varies within different populations of asthmatic children and how this might influence the results of our studies and those of other authors. I then critically review each component of the asthma phenotype and discuss its usefulness as· a marker of the disease within the population studied. I then go on to determine genetic associations between individual and parental genotype and phenotypic expression within children using a structured candidate gene approach. Following this approach it is evident that parts of the asthma phenotype, specifically airway hyperresponsiveness as measured by methacholine challenge varies consid~rably between different regional asthma centres.The reasons for this variation are unknown but limit the usefulness of this measure as an endpoint within our cohort 'of children. Subsequent detailed examination of other potential markers of- the asthma phenotype include an asthma severity score based on international guidelines, lung function measurements, total serum immunoglobulin E levels and the results of skin prick tests.
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Rode, Sandra Lee 1955. "FORAMINIFERA AS A TEST OF HERITABILITY OF SPECIATION POTENTIAL." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276479.
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If species selection shapes the history of clades, we should be able to detect its impact within well-established monophyletic descent groups. We should find that high rates of speciation/extinction are heritable. Demonstrating that high speciation/extinction rates have not been transmitted along known lines of descent would prove that species selection had not played an important role with the descent group under study. I have screened speciation rates within the Cenozoic planktonic foraminifera for heritability. Neither modified parent-offspring tests nor rank concordance tests reveal inheritance of this trait.
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Kraatari, M. (Minna). "The heritability and genetic risk factors of Modic changes." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526220550.
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Abstract Low back pain (LBP) is a highly prevalent musculoskeletal condition and the leading cause for workplace absenteeism. Lumbar disc degeneration (DD) is considered as a contributing factor to LBP. The role of genetic factors in the development of lumbar DD has been demonstrated to be significant, with heritability estimates ranging from 64% to 81%. Modic change (MC), a distinct phenotype of lumbar DD, is a subchondral and vertebral bone marrow change revealed only by magnetic resonance imaging (MRI). MC has been associated with LBP in both clinical samples and the general population. The genetic background of MC is largely unknown, and the heritability of MC has not previously been assessed. The aim of this study was to assess the heritability of MC using a twin study, identify predisposing genetic factors for MC in a family-based design using whole-exome sequencing and to identify genetic loci associated with MC using genome-wide association study (GWAS) meta-analysis. An additional aim was to study the prevalence, incidence and morphology of MC. The data consisted of two general population samples, the Northern Finland Birth Cohort 1966 (NFBC1966) and TwinsUK from the United Kingdom, as well as two Finnish families from the Oulu region. MC was found to be partly heritable with a heritability estimate of 30%. Two novel candidate genes, HSPG2 and MAML1, were found co-segregating with MC in two Finnish families. Both genes are important in the growth and differentiation of chondrocytes. Finally, a genetic locus on chromosome 9 was found to be significantly associated with MC using genome-wide meta-analysis of NFBC1966 and TwinsUK. These results showed that genetic factors play a role in the development of MC. In conclusion, this thesis increased the knowledge on the genetics of MC. However, the specific roles of these genes need to be studied furtherTiivistelmä Alaselkäkivun kansaterveydellinen merkitys on suuri, sillä jopa 84% aikuisista kärsii siitä elämänsä aikana. Selkäkivun vuoksi Suomessa kertyy yli 2 miljoona sairauslomapäivää vuodessa. Välilevyrappeumaa pidetään merkittävänä tekijänä alaselkäkivun synnyssä ja perinnölliset tekijät selittävät välilevyrappeuman synnystä jopa 74%. Modic-muutokset ovat selkärangan välilevyjen päätelevyjen ja subkondraalisen luun muutoksia, jotka voidaan havaita ainoastaan magneettikuvauksella. Niitä pidetään välilevyrappeuman alatyyppinä. Modic-muutosten on osoitettu olevan yhteydessä alaselkäkipuun, mutta etiologia tunnetaan huonosti. Perinnöllisyyden osuutta Modic-muutoksien synnyssä ei ole aiemmin tutkittu ja niiden taustalla vaikuttavat geneettiset tekijät ovat pääasiassa tuntemattomia. Tämän tutkimuksen tavoitteena oli arvioida perinnöllisyyden osuutta Modic-muutoksissa kaksoisaineistossa, tunnistaa Modic-muutoksille altistavia geneettisiä muutoksia perheaineistossa käyttäen eksomisekvensointia ja tunnistaa genomin alueita, jotka assosioituvat Modic-muutoksiin. Tutkimus perustui kahteen väestöperäiseen aineistoon: Pohjois-Suomen Syntymäkohorttiin 1966 ja TwinsUK-kaksosaineistoon Yhdistyneistä kuningaskunnista sekä kahteen pohjois-suomalaiseen perheeseen. Tutkimuksessa osoitettiin, että Modic-muutokset ovat perinnöllisiä ja, että perinnölliset tekijät selittävät noin 30% niiden ilmenemisestä. Lisäksi tutkimuksessa tunnistettiin kaksi uutta alttiusgeeniä; HSPG2- ja MAML1-geenit. Molemmilla geeneillä on tärkeä rooli rustosolujen kasvamisessa ja erilaistumisessa. Tutkimuksessa myös tunnistettiin kromosomista 9 genomin alue, joka assosioituu Modic-muutoksiin. Väitöskirjassani osoitettiin, että perinnöllisillä tekijöillä on merkitystä Modic-muutosten synnyssä. Kokonaisuudessaan tämä väitöskirja kasvattaa ymmärrystä Modic-muutoksista, mutta lisätutkimusta aiheesta tarvitaan
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Monzani, Benny. "Heritability and visual information processing in Body Dysmorphic Disorder." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/heritability-and-visual-information-processing-in-body-dysmorphic-disorder(afa1e779-4658-4ff3-af46-ce4a18eaf4f8).html.
Full textAbstract:
Body Dysmorphic Disorder (BDD) is a mental disorder characterised by an excessive preoccupation with a perceived defect in physical appearance, associated with significant distress and/or functional impairment as well as markedly high suicide rates. Its aetiology remains largely unknown, though believed to be related to a complex interplay of genetic, neurobiological, psychological and socio-‐cultural factors. Despite the alarmingly high suicide rates and the severity of this illness, BDD is widely under-diagnosed and under-investigated compared to other psychiatric conditions. The distinct studies included in this PhD will address some core questions about the heritability of BDD and its etiological relation to Obsessive-Compulsive Disorder (OCD) and Related Disorders (OCRDs); the current thesis also aims to investigate holistic visual processing in BDD. Specifically, using twin modelling methods, Studies 1 to 4 aimed to examine the heritability of BDD symptoms and skin picking behaviours in a large twin sample and to estimate the extent to which BDD shares genetic and environmental risk factors with other OCRDs (i.e. OCD, Hoarding Disorder, Trichotillomania and Skin Picking Disorder). Clinical observations, neuropsychological and neuroimaging studies suggest a tendency of BDD patients to selectively attend to details and excessively focus on minor flaws in physical appearance. Hence, the aim of Study 5 was to investigate the integrity of holistic visual processes in 25 BDD, compared to 25 healthy controls, using the inversion, composite, and navon tasks. The results of Studies 1 to 4 showed that BDD and OCRDs symptoms are moderately heritable traits, sharing a complex genetic architecture. Study 5 provided converging evidence from three experimental paradigms to suggest intact global visual processing in BDD. The findings have important implications for guiding genetic research and the study of environmental risk factors for BDD and OCRDs as well as for encouraging further examination of visual processing in BDD.
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Chen, Xu. "Accelerated estimation and inference for heritability of fMRI data." Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/67103/.
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In this thesis, we develop some novel methods for univariate and multivariate analyses of additive genetic factors including heritability and genetic correlation. For the univariate heritability analysis, we present 3 newly proposed estimation methods—Frequentist ReML, LR-SD and LR-SD ReML. The comparison of these novel and those currently available approaches demonstrates the non-iterative LRSD method is extremely fast and free of any convergence issues. The properties of this LR-SD method motivate the use of the non-parametric permutation and bootstrapping inference approaches. The permutation framework also allows the utilization of spatial statistics, which we find increases the statistical sensitivity of the test. For the bivariate genetic analysis, we generalize the univariate LR-SD method to the bivariate case, where the integration of univariate and bivariate LR-SD provides a new estimation method for genetic correlation. Although simulation studies show that our measure of genetic correlation is not ideal, we propose a closely related test statistic based on the ERV, which we show to be a valid hypothesis test for zero genetic correlation. The rapid implementation of this ERV estimator makes it feasible to use with permutation as well. Finally, we consider a method for high-dimensional multivariate genetic analysis based on pair-wise correlations of different subject pairs. While traditional genetic analysis models the correlation over subjects to produce an estimate of heritability, this approach estimates correlation over a (high-dimensional) phenotype for pairs of subjects, and then estimates heritability based on the difference in MZ-pair and DZ-pair correlations. A significant two-sample t-test comparing MZ and DZ correlations implies the existence of heritable elements. The resulting summary measure of aggregate heritability, defined as twice the difference of MZ and DZ mean correlations, can be treated as a quick screening estimate of whole-phenotype heritability that is closely related to the average of traditional heritability.
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Ramirez, de Leon Hector. "Method of pollination and heritability for seedling vigor in switchgrass." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2374.
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Switchgrass (Panicum virgatum L.) is a warm-season perennial bunchgrass native to North America. In addition to its importance as a forage grass, it has promise as a biofuel crop. However, its use is limited because the grass is difficult to establish. Improving seedling vigor is one approach for improving establishment. The objectives of this study were to: 1) select for increased seedling mass through half-sib family selection; 2) calculate an estimate of heritability for seedling mass; and 3) determine the mode of pollination of switchgrass. One cycle of selection was completed using a half-sib methodology. Seedling mass was determined in a series of growth chamber studies. The seed was produced in different space planted field nurseries in the College Station, TX area. Mean seedling weight of the base population (C0) was 0.014 gm seedling-1, while the mean seedling weight from the C1 cycle of selection was 0.029 gm seedling-1. Unfortunately, bulked seed from the base population was old and did not germinate well. Therefore, a new base population was recreated, and the C0 seedlings from this population were heavier than the C1 seedlings, 0.020 and 0.016 gm seedling-1,
respectively. The calculated heritability estimate was H2 = 0.6. Since the C0 and C1 nurseries were not grown on the same soil type, the lack of a positive response for seedling weight may be due to the different soil types. However, it may require another cycle of selection to determine if seedling mass can be positively impacted via half-sib selection. The mode of pollination of the species was determined by 1) observing pollen germination and tube growth in the pistils using fluorescent microscopy and 2) determining seed set with selfed plants. When self-pollinated, the pollen tubes never grew into the ovaries but when cross-pollinated the tubes readily grew to the micropyle. Also, when switchgrass plants were self-pollinated, viable seed were not produced. These findings indicate that switchgrass is highly self-sterile because a self-incompatibility mechanism prevents the pollen tubes from growing into the ovary of the same genotype.
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Williamson, Richard John. "Alcohol consumption and mental health : association, heritability and genetic overlap." Thesis, King's College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438980.
Full text
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Bonnet, Anna. "Heritability Estimation in High-dimensional Mixed Models : Theory and Applications." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS498/document.
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Nous nous intéressons à desméthodes statistiques pour estimer l'héritabilitéd'un caractère biologique, qui correspond à lapart des variations de ce caractère qui peut êtreattribuée à des facteurs génétiques. Nousproposons dans un premier temps d'étudierl'héritabilité de traits biologiques continus àl'aide de modèles linéaires mixtes parcimonieuxen grande dimension. Nous avons recherché lespropriétés théoriques de l'estimateur du maximumde vraisemblance de l'héritabilité : nousavons montré que cet estimateur était consistantet vérifiait un théorème central limite avec unevariance asymptotique que nous avons calculéeexplicitement. Ce résultat, appuyé par des simulationsnumériques sur des échantillons finis,nous a permis de constater que la variance denotre estimateur était très fortement influencéepar le ratio entre le nombre d'observations et lataille des effets génétiques. Plus précisément,quand le nombre d’observations est faiblecomparé à la taille des effets génétiques (ce quiest très souvent le cas dans les étudesgénétiques), la variance de l’estimateur était trèsgrande. Ce constat a motivé le développementd'une méthode de sélection de variables afin dene garder que les variants génétiques les plusimpliqués dans les variations phénotypiques etd’améliorer la précision des estimations del’héritabilité.La dernière partie de cette thèse est consacrée àl'estimation d'héritabilité de données binaires,dans le but d'étudier la part de facteursgénétiques impliqués dans des maladies complexes.Nous proposons d'étudier les propriétésthéoriques de la méthode développée par Golanet al. (2014) pour des données de cas-contrôleset très efficace en pratique. Nous montronsnotamment la consistance de l’estimateur del’héritabilité proposé par Golan et al. (2014)We study statistical methods toestimate the heritability of a biological trait,which is the proportion of variations of thistrait that can be explained by genetic factors.First, we propose to study the heritability ofquantitative traits using high-dimensionalsparse linear mixed models. We investigate thetheoretical properties of the maximumlikelihood estimator for the heritability and weshow that it is a consistent estimator and that itsatisfies a central limit theorem with a closedformexpression for the asymptotic variance.This result, supported by an extendednumerical study, shows that the variance of ourestimator is strongly affected by the ratiobetween the number of observations and thesize of the random genetic effects. Moreprecisely, when the number of observations issmall compared to the size of the geneticeffects (which is often the case in geneticstudies), the variance of our estimator is verylarge. This motivated the development of avariable selection method in order to capturethe genetic variants which are involved themost in the phenotypic variations and providemore accurate heritability estimations. Wepropose then a variable selection methodadapted to high dimensional settings and weshow that, depending on the number of geneticvariants actually involved in the phenotypicvariations, called causal variants, it was a goodidea to include or not a variable selection stepbefore estimating heritability.The last part of this thesis is dedicated toheritability estimation for binary data, in orderto study the proportion of genetic factorsinvolved in complex diseases. We propose tostudy the theoretical properties of the methoddeveloped by Golan et al. (2014) for casecontroldata, which is very efficient in practice.Our main result is the proof of the consistencyof their heritability estimator
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Salfati, Elias Levy Itshak. "Genetic determinants of cardiovascular disease : heritability and genetic risk score." Thesis, Paris 5, 2014. http://www.theses.fr/2014PA05S014/document.
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Les maladies complexes telles que les maladies cardio-Vasculaires (MCV) sont influencées par des facteurs génétiques et environnementaux. L’estimation du risque cardio-Vasculaire chez un individu est généralement évaluée par la sommation des facteurs de risque reconnu des MCV (p. ex. l’âge, le sexe, le tabac, la pression artérielle et le cholestérol). Dernièrement, plusieurs bio-Marqueurs ont été examiné pour leur aptitude à améliorer la prédiction des maladies cardio-Vasculaires au-Delà des facteurs de risques traditionnels. L’intérêt de découvrir de nouveaux loci est incité notamment par les découvertes qui émergent des études d'association pangénomique (GWAS) qui permettent de tester l’association de variation génétique au risque de contracter une maladie commune. Les GWAS ont considérablement amélioré notre connaissance de l'architecture génétique des maladies cardio-Vasculaires, à ce jour plus de 50 variations génétiques sont formellement associées à des maladies cardio-Vasculaires, de même plus de 200 marqueurs génétiques seraient associés à des facteurs de risque cardiovasculaire traditionnels (p. ex. le taux sanguin des lipides, la pression artérielle, l’indice de masse corporelle et le diabète de type 2). Le succès remarquable de ces études d’association, qui a permis l’identification de nombreux bio-Marqueurs, a conduit à une réévaluation des données génétiques dans le but de définir des informations cliniquement utiles pour limiter et mieux prédire les risques de maladies, grâce à une application plus efficace des stratégies de prévention. Dans cette thèse, nous examinons tout d'abord une nouvelle approche pour étudier l'architecture génétique de l'hypertension artérielle (HTA; facteur de risque majeur des maladies cardiovasculaires prématurées), puis nous avons constitué plusieurs modèles pour prédire le risque de développer une maladie coronarienne (MC; type le plus commun de MCV), enfin nous avons déterminé une base génétique commune du principal prédicteur de complications cliniques des maladies coronariennes – l'athérosclérose subclinique - afin d'ajouter une valeur pronostique supplémentaire en plus des scores de risque traditionnels à différents âges. Nous avons estimé l'héritabilité de la première mesure de la pression artérielle systolique (PAS) à ~25%/~45% et à ~30%/~37% pour la pression artérielle diastolique (PAD) chez les sujets d’origine Européenne (N = 8901) et d’origine Africaine (N = 2860) faisant respectivement partie de la cohorte Atherosclerosis Risk in Communities (ARIC), en accord avec les études antérieures. Par ailleurs, nous avons développé un moyen de combiner un score de risque génétique (SRC) – somme des effets génétiques parmi un ensemble de marqueurs – avec une évaluation indépendante du risque clinique, en utilisant un système d'équations log-Linéaire. Nous avons employé cet outil à la prédiction de la maladie coronarienne (MC) dans la cohorte ARIC. L'ajout d'un score de risque génétique (SRG) à un score de risque clinique (SRC) améliore à la fois la discrimination et l'étalonnage des maladies coronariennes dans la cohorte ARIC, et révèle par la même comment cette information génétique influence l'évaluation des risques ainsi que l’approche clinique. Enfin, parmi 1561 cas et 5068 contrôles (de la présence ou non de calcifications coronaires), faisant partie de plusieurs ensembles de données cliniques et génétiques disponibles via la base de données NCBI de Génotypes et Phénotypes (dbGAP), nous avons constaté qu’une augmentation d'un écart-Type dans le score de risque génétique de 49 bio-Marqueurs de MC est associée à 28 % d’augmentation de risque de développer une athérosclérose coronarienne subclinique diagnostiquée à un stade avancé (p=1.43x10-16). Cette augmentation du risque est significative dans chaque catégorie d'âge (de 15 ans en 15 ans) (0,01 > p > 9.4x10-7) et a été remarquablement similaire dans toutes les catégories d'âge (test d'hétérogénéité p = 0.98). (...)Complex diseases such as cardiovascular disease (CVD) are influenced by both genetic and environmental factors. Estimation of an individual’s cardiovascular risk usually involves measurement of risk factors correlated with risk of CVD (e.g. age, sex, smoking, blood pressure, and total cholesterol). Lately, several biomarkers have been evaluated for their ability to improve prediction of cardiovascular disease beyond traditional risk factors. The interest in novel loci is propelled notably by emerging discoveries from the advent of genome-Wide association studies (GWAS) of genetic variants associated with risk for common diseases. GWAS has greatly enhanced our knowledge of the genetic architecture of cardiovascular disease, yielding over 50 variants confirmed to be associated with CVD to date, as well as over 200 associated with traditional cardiovascular risk factors (e.g. lipids, blood pressure, body mass index, and type 2 diabetes mellitus). This recent and continuing success in discovering increasing numbers of robustly associated genetic markers has led to reassessment of whether genetic data can provide clinically useful information by refining risk prediction and moderating disease risk through a more efficient application of prevention strategies. In this thesis, we first address novel approach to survey the genetic architecture of hypertension (i.e. major risk factor for premature CVD), then construct risk prediction models for coronary artery disease (CAD; i.e. most common type of CVD) and finally establish a common genetic basis of the strongest predictor of clinical complications of CAD, subclinical atherosclerosis, to add incremental prognostic value above traditional risk scores across a range of ages. We show that, for first visit measurements, the heritability is ~25%/~45% and ~30%/~37% for systolic (SBP) and diastolic blood pressure (DBP) in European (N=8,901) and African (N=2,860) ancestry individuals from the Atherosclerosis Risk in Communities (ARIC) cohort, respectively, in accord with prior studies. Then we present a means to combine a polygenic risk score - genetic effects among an ensemble of markers - with an independent assessment of clinical risk using a log-Link function. We apply the method to the prediction of coronary heart disease (CHD) in the ARIC cohort. The addition of a genetic risk score (GRS) to a clinical risk score (CRS) improves both discrimination and calibration for CHD in ARIC and subsequently reveal how this genetic information influences risk assessment and thus potentially clinical management. Finally, Among 1561 cases and 5068 controls, from several clinical and genetic datasets available through the NCBI's database of Genotypes and Phenotypes (dbGAP), we found a one SD increase in the genetic risk score of 49 CAD SNPs was associated with a 28% increased risk of having advanced subclinical coronary atherosclerosis (p = 1.43 x 10-16). This increase in risk was significant in every 15-Year age stratum (.01 > p > 9.4 x 10-7) and was remarkably similar across all age strata (p test of heterogeneity = 0.98). We obtained near identical results and levels of significance when we restricted the genetic risk score to 32 SNPs not associated with traditional risk factors. Accordingly, common variation largely recapitulates the known heritability of blood pressure traits. The vast majority of this heritability varies by chromosome, depending on its length, and is largely concentrated in intronic and intergenic regions of the genome but widely distributed across the common allele frequency spectrum. Respectively, our proposed method to combine genetic information at established susceptibility loci with a nongenetic risk prediction tool facilitates the standardized incorporation of a GRS in risk assessment. (...)
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Ganunga, Rosan Paterson. "Genotypic and phenotypic chacterization of maize testcross hybrids under stressed and non stressed conditions." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4827.
Full textAbstract:
Drought and low soil nitrogen are major factors limiting maize production in Sub-Saharan Africa. Genotypic and phenotypic characterization of maize testcross hybrids developed from four biparental populations: CML441 x CML444, CML440 x COMPE, CML444 x K64R and CML312 x NAW was conducted. The objectives were (a) to evaluate the performance of F2:3 line testcrosses across stressed and non-stress conditions, (b) to estimate heritabilities for grain yield and secondary traits, (c) to assess the relationship between testing environments, (d) to estimate genetic correlations among relevant traits, (e) to estimate direct and indirect genetic gain from selection, and (e) to have a preliminary assessment of the efficiency of marker-assisted selection. Studies were conducted under no nitrogen fertilization, low nitrogen, drought, well- watered and high nitrogen in Malawi and Zimbabwe. About 100 entries from each population were tested using an alpha lattice design with two replications at all locations. Traits measured were grain yield, plant height, anthesis date, anthesis-silking interval, ears per plant, grain moisture at harvest and leaf senescence. Highest grain yield across environments was obtained from population CML444 x K64R (3.82 Mg ha-1) and the lowest from CML440 x COMPE (3.64 Mg ha-1). Testcrosses from CML441 x CML444 and CML444 x K64R had higher heritability estimates compared to CML440 x COMPE and CML312 x NAW. Drought and high nitrogen environments had higher heritability estimates than low nitrogen and well-watered conditions. Drought and well-watered environments discriminated testcrosses in a similar manner as well as high and low nitrogen environments. All populations had negative correlations between grain yield and anthesis silking interval, while positive correlations were observed between grain yield and ears per plant. No consistent differences were observed between overall means of best and worst marker based selected line testcrosses across populations and environments. Highest direct expected genetic gains were observed from high nitrogen environments. Direct selection under specific environments (e.g. drought ) was estimated to be more beneficial than indirect selection in other environments.
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Mateo, Moncada Rafael Arturo. "Evaluation and heritability of ergot resistance derived from sorghum germplasm IS8525." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/206.
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Sorghum (Sorghum bicolor [L.] Moench) is fifth among the major cereal crops in the world in terms of production area and total production. Grain sorghum can be successfully produced in a wide range of environments, its productivity is severely limited by pathogens, insects and abiotic stresses. One of these pathogens is Claviceps africana Frederickson Mantle & de Milliano, commonly known as ergot. As is the case with many sorghum diseases, the best long term approach to control ergot may be the use of genetic resistance. There is limited information about resistance to C. africana in sorghum, and the reported resistance in most lines is fertility-based. Dahlberg (1999) first reported the line IS8525 to have the most tolerance to ergot of any of the accessions screened in Puerto Rico. The specific objectives of this research are: (1) to confirm the presence of C. africana resistance in IS8525 germplasm, (2) to determine if the resistance in IS8525 is pollen mediated or ovule based, and (3) to determine if the resistance in IS8525 is heritable and stable across environments. Ergot vulnerability ratings were determined for two recombinant inbred line populations, IS8525D and IS8525J, in four locations during 2001. Also, ergot vulnerability ratings were evaluated in four test-cross populations (using as testers A3Tx623 and A3Tx623) in two locations. Evaluations of the original parents indicate that ergot tolerance in IS8525D parent was consistently better than that in IS8525J parent. As expected, neither parent provided complete resistance. The IS8525J recombinant inbred line population showed significantly more ergot susceptibility than the IS8525D recombinant inbred line population and this trend was consistent across environments. Variation for ergot vulnerability amo ng recombinant inbred lines for both populations was detected, but the amount of variability was environment dependent. In the testcross hybrids, all four populations were susceptible to ergot, primarily due to male sterility in the hybrids, confirming that the tolerance shown in IS8525 germplasm is mostly pollen mediated. However, a greater level of tolerance in the IS8525 hybrid checks confirmed the reports of tolerance by Dahlberg et al. (1998) and Reed et al. (2002).
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O'Connell, Anne R., and n/a. "Heritability and phenotypic analysis of high embryonic survival in prolific ewes." University of Otago. Department of Anatomy & Structural Biology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20091009.160105.
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A significant proportion of potential lambs are lost (commonly 15-20%) between ovulation and day 30 of gestation. Moreover, little is known about factors associated with multiple birth capacity of the uterus which would be necessary to convert gains in ovulation rate to the birth of live lambs. This project has investigated the relationship between maternal uterine and hormonal environment as well as the heritability of embryonic survival (ES) in prolific ewes.
Litter size (LS) from known ovulation rate (OR) records (n=6393) collected over 16 years were analysed for heritability. ASReml analysis reported ES to be a trait of low repeatability (r� = 0.103) and heritability (h� = 0.04) which is consistent with earlier studies of this trait. However, pedigrees of outlier animals indicated a segregation pattern consistent with a single autosomal gene with a major affect on enhanced ES. From this flock, closely related high ovulation rate ewes with significantly different litter sizes (High ES; OR2.6/LS2.4 versus Low ES; OR2.9/LS1.6) were selected for further study.
The anatomy and gene expression of the uterus collected at day 14 of the oestrous cycle (n=5 High and n=5 Low ES ewes) and day 16 of gestation (n=14 high and n=10 Low ES ewes) as well as systemic concentrations of hormones indicative of uterine (activin-A, follistatin) and ovarian (inhibin-α, progesterone) function during the oestrous cycle and early gestation were compared.
Progesterone concentrations were found to rise earlier in high ES ewes with a difference in number of ewes with detectable levels of progesterone apparent by day 4 of gestation. The peak concentration and slope of progesterone increase as well as plasma profiles of oestradiol and inhibin-α were not different between groups.
A number of pathways worthy of closer investigation were implicated by microarray analysis with Ingenuity Pathway Analysis, Pubmatrix, and candidate gene approaches. In particular, the altered expression of many immune cell factors suggests that high ES ewes have maternal gene expression of the inflammatory pathways favourable to embryo implantation.
The plasma concentration of activin, but not follistatin, was found to be significantly higher in low ES ewes, a difference that remained apparent when the concentration of follistatin was corrected for individual samples. Furthermore, the concentration of activin, but not follistatin, was significantly elevated on day 16 of gestation in the uterine fluid of low ES ewes.
Further investigation of the pattern of gene expression during the oestrous cycle and early gestation (day10-16 oestrus and days10-20 gestation) revealed that a significant increase in follistatin mRNA in the luminal epithelia and interacting trophoblast cells of the embryo occurs on day 18 and 20 of gestation. It is likely the appropriate balance between activin and follistatin during the time of implantation enhances embryonic survival in this line of ewes. This may be secondary to or concomitant with the observed earlier rise in progesterone concentration. The implication that embryo survival may be positively influenced by a single autosomal gene has important implications for New Zealand's agricultural industry.
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Resende, Rafael Tassinari. "Regional Heritability Mapping and GWAS for molecular breeding in eucalyptus hybrids." Universidade Federal de Viçosa, 2017. http://www.locus.ufv.br/handle/123456789/11670.
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Embora os estudos de associação genômica (GWAS) forneçam informações valiosas na descodificação das relações entre a variação gênica e os fenótipos complexos, esta técnica explica uma pequena fração da herdabilidade. O mapeamento de herdabilidades regionais (RHM) fornece estimativas de herdabilidade para segmentos genômicos que contêm efeitos alélicos raros e que contribuem individualmente com baixa variação ao ponto de serem detectados pela GWAS. Neste estudo foi realizado a GWAS e o RHM para sete características de crescimento, madeira e resistência à doenças em uma população 768 árvores híbridas de Eucalyptus usando o moderno Chip Illumina EuCHIP60K. As herdabilidades genômicas totais representaram grandes proporções (64-89%) de herdabilidades baseadas em pedigree, fornecendo evidências adicionais de que características complexas em eucaliptos são controlados por muitas variantes ao longo do genoma, cada uma com pequenas contribuições para a variância fenotípica. O RHM detectou 26 QTLs (Quantitative Trait Loci) abrangendo 2.191 SNPs (Single Nucleotide Polymorphism), enquanto que a GWAS detectou 13 associações. Os QTLs detectados via RHM e GWAS explicaram individualmente 5 a 15% e 4 a 6% da herdabilidade genômica, respectivamente. O RHM foi superior à GWAS na captura de maiores proporções de herdabilidade genômica. Semelhantemente a QTLs previamente mapeados, os resultados destacaram as regiões genômicas que podem ser utilizadas em estudos mais aprofundados para descoberta de genes. Os RHM-QTLs contendo uma combinação de variantes comuns e raras representam um avanço para incorporar conhecimento prévio da arquitetura genética subjacente em modelos de predição genômica.
Although genome-wide association studies (GWAS) have provided valuable insights into the decoding of the relationships between sequence variation and complex phenotypes, they have explained little heritability. Regional heritability mapping (RHM) provides heritability estimates for genomic segments containing both common and rare allelic effects that individually contribute too little variance to be detected by GWAS. We carried out GWAS and RHM for seven growths, wood and disease resistance traits in a breeding population of 768 Eucalyptus hybrid trees using EuCHIP60K. Total genomic heritabilities accounted for large proportions (64 89%) of pedigree-based trait heritabilities, providing additional evidence that complex traits in eucalypts are controlled by many sequence variants across the frequency spectrum, each with small contributions to the phenotypic variance. RHM detected 26 quantitative trait loci (QTLs) encompassing 2,191 single nucleotide polymorphisms (SNPs), whereas GWAS detected 13 single SNP trait associations. RHM and GWAS QTLs individually explained 5 15% and 4 6% of the genomic heritability, respectively. RHM was superior to GWAS in capturing larger proportions of genomic heritability. Equated to previously mapped QTLs, our results highlighted genomic regions for further examination towards gene discovery. RHM-QTLs bearing a combination of common and rare variants could be useful enhancements to incorporate prior knowledge of the underlying genetic architecture in genomic prediction models.
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Pillinger, Rebecca. "Differential heritability and environmentality of intelligence and achievement across socioeconomic status." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681989.
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While heritability of the Wechsler Intelligence Scales for Children (WISC) subscales has been estimated by several studies, none have investigated differential heritability or environmentality. Analysing a US sample of around 300 pairs of identical and non-identical 7 year old twins, we find significant differential heritability and/or environmentality across socioeconomic status (SES) for all subscales we examine except Digit Span and Coding. There has also been no previous investigation of how the genetic and environmental contributions to the relationship between intelligence and achievement change across SES. Using the same sample, we do not find any change in the components attributable to genes or to the environment of the covariance between intelligence (measured by WISC Full Scale IQ) and achievement (measured by the Wide Range Achievement Test (WRAT) sub tests Spelling, Reading and Arithmetic) . However, we find that the component of t he variance of WRAT Spelling attributable to genes increases with increasing parental education, as does the component of the variance of WRAT Reading attributable to environmental factors not experienced by both twins in a pair, leading to decreasing correlations with increasing parental education for these subtests. The findings have implications for the use of intelligence tests to select into educational opportunities. They suggest that WISC Full Scale IQ cannot determine which children of less educated parents would achieve highest were they to move to an environment similar to that provided by more educated parents. They also indicate that Digit Span and Coding are the fairest subscales of the WISC in that genetic and environmental factors are responsible for differences between individuals to the same degree across SES. We also focus on the methodology needed to carry out the analyses, evaluating existing techniques for estimating differential heritability and environmentality, stressing some important interpretational issues, and presenting new extensions to the basic multilevel genetic model that allow us to investigate the questions of interest.
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Silva, Carlos H. "A Proposed Framework for Establishing Optimal Genetic Designsfor Estimating Narrow-sense Heritability." NCSU, 2000. http://www.lib.ncsu.edu/theses/available/etd-20000414-113213.
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We develop a framework for establishing sample sizes in breeding plans, so that one is able to estimate narrow-sense heritability with smallest possible variance, for a given amount of effort. We call this an optimal genetic design. The framework allows one to compare the variances of estimators of narrow-sense heritability, when estimated from each one of the alternative plans under consideration, and does not require data simulation, but does require computer programming. We apply it to the study of a peanut (Arachis hypogaea) breading example, in order to determine the ideal number of plants to be selected at each generation. We also propose a methodology that allows one to estimate the additive genetic variance for the estimation of the narrow-sense heritability using MINQUE and REML, without an analysis of variance model. It requires that one can build the matrix of genetic variances and covariances among the subjects on which observations are taken. This methodology can be easily adapted to ANOVA-based methods, and we exemplify by using Henderson's Method III. We compare Henderson's Method III, MINQUE, and REML under the proposed methodology, with an emphasis on comparing these estimation methods with non-normally distributed data and unbalanced designs. A location-scale transformation of the beta density is proposed for simulation of non-normal data.
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Schmidt, Paul [Verfasser], and Hans-Peter [Akademischer Betreuer] Piepho. "Estimating heritability in plant breeding programs / Paul Schmidt ; Betreuer: Hans-Peter Piepho." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2020. http://d-nb.info/1209196328/34.
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AGBARY, ABDUL WALLY. "HERITABILITY AND PHYSIOLOGY OF DROUGHT TOLERANCE IN SORGHUM (SORGHUM BICOLOR (L.) MOENCH)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187991.
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Physiological responses of 12 sorghum (Sorghum bicolor L.) genotypes previously classified as drought resistant and susceptible upon grain yield basis were evaluated under dry and wet moisture treatments at Tucson, Arizona in 1983. In addition, the relationship of these physiological responses and their heritability estimates were also determined. Apparent photosynthesis, transpiration, diffusive resistance, temperature differentials, and leaf temperature were measured under field conditions at three intervals from planting date: 48, 62, and 77 days, respectively. Stomatal density and epicuticular wax content were determined toward the end of the season when full canopy development was reached. Stress significantly affected all characteristics measured for each genotype by a reduction in apparent photosynthesis rates, transpiration, and temperature differentials, and an increase in diffusive resistance, leaf temperature and stomatal density. The wax content response varied among genotypes irrespective of the dry and wet moisture treatments. Except for the wax content and stomatal density, all the other parameters demonstrated a high significant correlation with photosynthesis at .001 level; nevertheless, greater values were observed in the stress treatment. Analysis of variance failed to detect significant differences among the 12 germplasm sources, except for the stomatal density. Multiple regression analysis showed that leaf diffusive resistance was the first variable incorporated for photosynthesis prediction in both the dry and wet treatments. The offspring and mid-parent regression for each characteristic under both treatments provided heritability estimates (h('2) (+OR-) SE), indicating higher heritability values under the dry treatment.
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Hakiza, John Johnson. "Quantitative analysis and heritability of host resistance to exserohilum turcicum in maize /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859313347568.
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Barthold, Julia A. "A demographic perspective on trait heritability and sex differences in life history." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:94f04aac-182f-466b-a267-179d68db398f.
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Biologists have long used demographic approaches to answer questions in ecology and evolution. The utility of these approaches has meant a constant development and refinement of methods. A key milestone has been the development of phenotype structured population models that link ecology and evolution. Moreover, biostatistical research steadily improves methods to coax demographic information from scarce data. In this thesis, I build upon some of the recent advances in the field. My first three studies focus on the consequences of sex differences in life history for population dynamics. Firstly, I test whether males matter for the dynamics of African lion (Panthera leo) populations via a previously unquantified mechanism: the inheritance of phenotype from father to offspring. Secondly, I develop a method to estimate age-specific mortality rates for both sexes in species where one of the sexes disperses around the age of maturity. Thirdly, I apply this method to study variation in mortality between the sexes and between two populations of African lions. After these three chapters, which make contributions to the field of sex-structured population dynamics, I focus on the integration of phenotype structured modelling and quantitative genetics. I illustrate how heritability of a quantitative character that develops with age depends on (i) viability selection, (ii) fertility selection, (iii) the development of the phenotype with age, and (iv) phenotype inheritance from parents to offspring. Our results question the adequacy of quantitative genetics methods to obtain unbiased estimates of heritability for wild populations. This thesis advances our understanding of population development over ecological time scales. This knowledge has applications in conservation and population management, but also contributes to untangling evolutionary processes in wild animals.
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Vannier, Nathan. "The clonal plant microbiota : assembly rules, heritability and influence on host phenotype." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B027/document.
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Les plantes vivent en association avec une grande diversité de microorganismes qui forment son microbiota. Ce microbiote fournit des fonctions clés qui influencent tous les aspects de la vie d'une plante, de l'établissement à la croissance jusqu'à la production. Cette thèse a pour intention de déterminer les règlent d'assemblage du microbiote et ses conséquences pour le phénotypel l'adaptation et l'évolution des plantes. Pour atteindre cet objectif nous avont utilisé différentes approches expérimentales comprenant des plantes clonales comme organismes modèles ainsi que des mésocosmes prairiaux pour analyses à l'échelle des communautés. Nos résultats ont démontré i) que les Champignons Mycohiziens à Arbuscules induisent d'important es variations phénotypiques pour les traits des plantes clonales impliqués dans l'exploration de l'espace et l'exploitation des ressources. Ces changements dépendent de l'identité des symbiontes et altèrent les capacités des plantes à développer des réponses plastiques à l'hétérogénéité environnementale. ii) Les plantes ont évolué un méchanisme permettant la transmission d'une partie de leur microbiote a leur descendance, assurant la qualité de leur habitat. iii) Le contexte spécifique des communautés de plantes est un facteur majeur structurant l'assemblage du microbiota des plantes à échelle locale. L'abondance de certaines espèces de plante dans le voisinage d'une plante cible augmente ou diminue la diversité de son microbiote, déterminant in fine ses performances. De manière générale, cette thèse démontre l'importance des organismes symbiotiques dans la compréhension de l'adaptation et de l'évolution des plantesPlants live in association with a wide diversity of microorganisms forming the microbiota. The plant microbiota provides a variety of key functions that influence many aspects of plant's life comprising establishment, growth and reproduction. The present thesis aims at determining the assembly rules of the plant microbiota and its consequences for plant phenotype, adaptation and evolution. To fulfill this objective, we used different experimental approaches using either clonal plants as model organisms or grassland mesocosms for community-wide analyses. Our results demonstrated i) that Arbuscular Mycorrhizal Fungi induce important phenotypic variations in clonal plants traits involved in space exploration and resources exploitation. These changes depended on the identity of the symbionts and altered the plants ability to produce plastic responses to environmental heterogeneity. ii) Plants have evolved a mechanism allowing the transmission of a part of their microbiota to their progeny, ensuring thus their habitat quality. iii) The plant community context is a major factor structuring local plant microbiota assembly. Particular plant species identity in the neighborhood increase or decrease the microbiota diversity and ultimately determine the focal plant performance. This thesis overall demonstrates the importance of symbiotic microorganisms in the understanding of the plant adaptation and evolution. From the knowledges acquired we developed a novel understanding of symbiotic interactions in clonal plants by extending the holobiont theory to the meta-holobiont theory
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Myczkowski, Mirina Luiza [UNESP]. "Variabilidade genética para o teor de óleo entre progênies autofecundadas de mamona (Ricinus cummunis L.) da cultivar guarani." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/86470.
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myczkowski_ml_me_botfca.pdf: 94102 bytes, checksum: acf2ae8422a1d023a113297ec3036a90 (MD5)O presente trabalho teve como objetivo avaliar a variabilidade genética para teor de óleo entre progênies autofecundadas da cultivar de mamona Guarani. O material utilizado foi constituído de 135 progênies obtidas de plantas individuais, por meio de autofecundações artificiais, divididas em três experimentos e parcelas com 10m2. As avaliações foram realizadas em duas localidades, em Araçatuba - SP e em São Manuel - SP, na Fazenda Experimental São Manuel, da Faculdade de Ciências Agronômicas – UNESP/Botucatu. Foi avaliado o teor de óleo obtido por meio do método químico Soxhlet. Para cada localidade foram realizadas análises estatísticas segundo o delineamento de blocos ao acaso e também uma análise conjunta para os dois locais. Foram determinados os parâmetros genéticos, variância genética e coeficiente de herdabilidade. Os quadrados médios da interação de progênies por locais avaliadas na análise conjunta foram significativos a 5% de probabilidade pelo teste F em todos os experimentos, o que define a existência de comportamento diferencial de progênies em relação aos locais quanto ao teor de óleo. Os quadrados médios da análise de variância entre progênies dentro de locais apresentaram significância a 5% de probabilidade pelo teste F em todos os experimentos de Araçatuba, mostrando a existência de diferenças genéticas entre progênies, já nos experimentos de São Manuel os quadrados médios não foram significativos indicando assim ausência ou baixa variabilidade genética para teor de óleo. A média de teor de óleo, em São Manuel foi 43,22%, variando de 34,87% a 49,24%. Em Araçatuba, a média foi 43,59%, variando de 30,24% a 53,60%. A variância genética e o coeficiente de herdabilidade foram, respectivamente 0.32 e 0,10 para São Manuel e 4,87 e 0,44 para Araçatuba. Estes valores mostram a possibilidade de sucesso na seleção para teor de óleo nas condições de Araçatuba.
The purpose of the research was to evaluate the genetic variability for oil content among lines of castor bean, cv. Guarani. Using artificial self- fertilizations, 135 lines were obtained from individual plants and tested in two locations in the state of São Paulo : Araçatuba and São Manuel, utilizing randomized block design with three replications and plots with 10m2. Oil content was determined by the Soxhlet chemical method. Individual and joint analysis of variance were made to estimate genetic parameters. The mean squares of the line x location interaction were significant by the F test with 5% of probability, that demonstrated the existence of differential behavior of lines due locations for oil content. The mean squares of the variance analysis among lines were significant by the F test with 5% of probability in Araçatuba, showing the existence of genetic differences among lines. However, in São Manuel, the mean squares were not significant, showing absence or low genetic variability for oil content. Average of line oil content, in São Manuel was 43.22% (from 34.87% to 49.24%). In Araçatuba the oil content mean was 43.59% (from 30.24% to 53.6%). Genetic variance and heritability coefficients were respectively 0.32 and 0.10 for São Manuel and 4.87 and 0.44 for Araçatuba. Those values show the possibility to improve the oil content by selection in Araçatuba conditions.
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Nasser, Mansour Mohamed. "Heritability and morpho-physiology of drought tolerance in lines of Middle Eastern wheat." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327347.
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Billardon, Fannie. "Heritability of Flight Energetics and its Associated Traits in the Bumblebee Bombus Impatiens." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30164.
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Recent studies suggest a possible correlated evolution of wing morphology, wing beat frequency, muscle biochemistry and flight metabolic rate in bees. In order to investigate the degree to which natural selection can act on these traits, an estimation of heritability was required. Commercial and laboratory reared colonies from wild caught queens were used to estimate narrow-sense (h2) and broad-sense (H2) heritability of flight metabolic rate and its associated traits in the bumblebee Bombus impatiens. h2 estimates obtained from parent-offspring regressions were not statistically significant. H2 estimates were significant for morphological traits (body mass and wing morphology) as well as whole-animal traits (flight and resting metabolic rate, wing beat frequency) in both populations. We suggest that queens have a decrease in flight performance as a result of a trade-off between flight and fecundity, explaining the lack of significance in parent-offspring regressions.
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Silva, Carlos H. O. "A proposed framework for establishing optimal genetic designs for estimating narrow-sense heritability." Raleigh, NC : North Carolina State University, 2000. http://www.lib.ncsu.edu/etd/public/etd-8321114310051041/etd.pdf.
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Piqueras, Matias. "HERITABILITY FOR SOCIAL TRUST ACROSS SOCIOECONOMIC STATUS: : Is There a Gene-Environment Interaction?" Thesis, Uppsala universitet, Statsvetenskapliga institutionen, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-394876.
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In political science literature, the development of social trust is often explained in terms of the influence of different environmental factors, socioeconomic status (SES) being one of the most important. Yet, even though there is empirical support of a genetic component in the expression of social trust, less is known about its interaction with environmental factors. The present study aims to explore heritability of social trust across socioeconomic status using a twin-design that tests potential gene-environment (GxE) interactions. Moreover, the study explicitly tests the hypothesis that different levels of SES may moderate the influence of genetic and environmental effects on social trust. Data comes from the Swedish Twin Registry and consist of 1535 twin pairs born between 1943–1959. Social trust was measured through self-report on a scale of 1–10. Socioeconomic status was assessed as a dichotomized variable of high/low SES, determined on the basis of the father’s occupation during the twin’s childhood or adolescence. To test whether SES interacted with genetic and environmental effects for social trust, I used structural equation modeling (SEM). Results from the best fitting model show that social trust has a significant genetic component, with an estimated heritability of 0.41 in low SES and 0.33 in high SES. Results showed no evidence for a significant difference in heritability between low and high SES. Accordingly, it can be concluded that the results of the study do not support the hypothesis that SES moderate the influence of genetic effects on social trust.
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Määttä, J. (Juhani). "The heritability and morphology of lumbar Modic changes and their association with pain." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526214047.
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Abstract Low back pain (LBP) causes enormous costs to society. Certain magnetic resonance imaging (MRI) findings, including disc degeneration and disc herniation, have been associated with LBP in epidemiologic studies. Even though LBP should be considered a biopsychosocial condition, there is a need to define the possible existence of specific pathological conditions beyond LBP. One of these possible conditions is Modic change (MC). Modic changes are subchondral and vertebral bone marrow changes revealed by MRI. Although their association with LBP has been previously studied, some results remain contradictory, and we need to explore MC more thoroughly and to determine whether they are a feature of intervertebral disc degeneration or whether they exist in isolation. Moreover, it is unknown whether heritability is a contributing factor to MC. This study explored the heritability and morphology of MC and their association with severe, prolonged and disabling LBP. The data consisted of two general population samples, TwinsUK from the United Kingdom (mainly female), and the Hong Kong Disc Degeneration Cohort (HKDDC) from Hong Kong, China. The TwinsUK sample included a longitudinal ten-year follow-up, whereas the HKDDC sample was cross-sectional. The heritability of MC was found to be 30%. Modic changes were associated with other MRI findings such as disc degeneration, disc displacement and Schmorl’s nodes. A greater size of MC increased these associations. Type 1 MC were more strongly associated with disc displacement and disc degeneration than Modic type 2 change. Modic changes appeared to be independently associated with disabling LBP; severe, prolonged LBP; and back-related disability. Posterior MC and MC in the whole antero-posterior (AP) length of the vertebral body were more strongly associated with severe, prolonged LBP than other MC. A greater number and size of MC increased this association. In terms of disc degeneration, MC were independently associated with loss of disc height and disc signal intensity. Incident MC were independently associated with loss of disc height and disc bulge in a ten-year follow-up. Modic changes are heritable, and are associated with severe and disabling LBP. The location, size and number of MC affect the association of MC with other MRI findings, LBP and back-related disabilityTiivistelmä Alaselkäkivusta aiheutuu valtavat kustannukset yhteiskunnalle. Tietyt magneettikuvauslöydökset, kuten välilevyrappeuma ja välilevytyrä, on yhdistetty alaselkäkipuun epidemiologisissa tutkimuksissa. Alaselkäkipua arvioidaan yleensä biopsykososiaalisen mallin avulla, koska sen syytekijät tunnetaan huonosti. Lannerangan Modic-muutoksia pidetään yhtenä mahdollisena alaselkäkivun syytekijänä. Modic-muutokset ovat rustonalaisia, nikaman luuytimen muutoksia, jotka näkyvät magneettikuvantamisella. Tulokset Modic-muutosten ja alaselkäkivun yhteydestä ovat kuitenkin ristiriitaisia. Modic-muutosten sijainnin, koon ja muodon vaikutus alaselkäkipuun tunnetaan edelleen puutteellisesti. Lisäksi niiden perinnöllisyys on epäselvä. Tässä tutkimuksessa tarkasteltiin Modic-muutosten perinnöllisyyttä ja tarkempaa morfologiaa, kuten sijaintia ja kokoa lannerangassa, sekä selvitettiin niiden yhteyttä haittaavaan ja voimakkaaseen alaselkäkipuun. Tutkimus perustui kahteen väestöperäiseen aineistoon: TwinsUK-kaksosaineistoon (pääosin naisia) Yhdistyneistä kuningaskunnista ja Hong Kong Disc Degeneration -kohorttiin Hongkongista, Kiinasta. TwinsUK-aineisto sisälsi seurantatietoja 10 vuoden ajalta, ja Hongkongin aineisto oli kerätty yhdestä aikapisteestä. Modic-muutosten perinnöllisen osuuden todettiin olevan 30 %. Modic-muutokset olivat yhteydessä muihin magneettikuvauslöydöksiin kuten välilevyrappeumaan, välilevypullistumaan ja Schmorlin keräsiin. Tyypin 1 Modic-muutokset olivat voimakkaammin yhteydessä välilevypullistumiin ja -rappeumaan kuin tyypin 2 muutokset. Modic-muutokset olivat yhteydessä toimintakykyä alentavaan ja voimakkaaseen, pitkittyneeseen alaselkäkipuun. Koko nikaman läpimitan käsittävät ja nikaman takaosassa sijaitsevat muutokset olivat voimakkaammin yhteydessä alaselkäkipuun. Muutosten suurempi koko ja yhteislukumäärä lannerangassa voimistivat sen yhteyttä alaselkäkipuun. Modic-muutokset olivat yhteydessä välilevyn madaltumiseen ja signaali-intensiteetin laskuun. Kymmenen vuoden seuranta-aikana ilmaantuneet Modic-muutokset olivat yhteydessä välilevyn madaltumiseen ja välilevypullistumaan. Modic-muutokset ovat perinnöllisiä ja ne ovat yhteydessä voimakkaaseen sekä toimintakykyä heikentävään alaselkäkipuun. Muutosten tyypin lisäksi niiden sijainti, koko ja lukumäärä tulee huomioida alaselkäkipua arvioitaessa
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Welsh, Claire Elizabeth. "Heritability analyses of musculoskeletal conditions and exercise-induced pulmonary haemorrhage in thoroughbred racehorses." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/4862/.
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Musculoskeletal conditions and exercise-induced pulmonary haemorrhage are commonly diagnosed in Thoroughbred racehorses worldwide, and have serious consequences for racehorse welfare and the racing economy. Despite increasing interest in the study of genetic susceptibility to disease from the veterinary research community as a whole over past decades, the Thoroughbred has been largely ignored as a study group. The availability of software capable of complex genetic analyses using large, unbalanced pedigrees has made the study of genetic susceptibility to disease a realistic prospect for veterinary researchers. This study aimed to complete preliminary analyses of the genetics of a number of important musculoskeletal conditions, and of exercise-induced pulmonary haemorrhage, in two different Thoroughbred populations. Multivariable regression analyses were performed to identify important environmental risk factors for each condition in each population, and heritability analyses were conducted. Genetic correlations between disease conditions were also investigated. Fracture, tendon injury, suspensory ligament injury, osteoarthritis and EIPH/epistaxis were found to be heritable traits in the Hong Kong population. Distal limb fracture, SDFT injury and epistaxis were also found to be heritable in the UK Thoroughbred population. Most heritability estimates were small or moderate in magnitude. Selective breeding strategies that identify those animals with low genetic risk could play a part in future efforts to reduce the incidence of these conditions, in conjunction with favourable environmental manipulations based on research evidence. Due to low heritability, most of the conditions studied here would reduce in incidence slowly if selective breeding were implemented, thus strategic environmental manipulations would be warranted alongside such longer-term efforts to provide effective incidence reductions. A number of conditions were found to be positively genetically correlated, suggesting that risk reduction through breeding could reduce the risk of multiple diseases concurrently. For example, fracture and osteoarthritis were found to be positively genetically correlated (0.85 – 0.89) in the Hong Kong racehorse population. However, using the Hong Kong Thoroughbred population dataset, EIPH/epistaxis and tendon injury were negatively genetically correlated, which suggests that reduction in genetic risk of one of these may lead to increased genetic risk of the other. iii Measures of the durability and performance of racehorses were investigated to assess whether they were heritable traits in the UK and Hong Kong racehorse populations, and to assess their relationship to the disease conditions studied. Selection based on more holistic measures of horse health and longevity such as ‘career length’ could be a more attractive prospect for stakeholders, as this could forego the need to select for many different traits individually. Career length, number of starts over the career, and the level of earnings were all heritable traits in both populations. These holistic traits were found to have variable relationships with the disease conditions studied in each population. These analyses are the first to assess the genetic contribution to risk for many important diseases in the Thoroughbred. They provide a starting point from which further investigations into the applicability of genetic manipulations could yield realistic and achievable tools for racing stakeholders to use to ‘improve’ the breed in future.
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Lietzenmaier, Sonja. "Untersuchung zur Heritabilität von Tagesmüdigkeit und Aufmerksamkeit anhand einer klassischen Zwillingsstudie." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-148745.
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Velie, Brandon D. "Repeatabilities and Heritabilities of Behavior Traits and Their Relationship With Performance." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03292007-223828/.
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The object of this study was to estimate repeatabilities and heritabilities of indirect measures of pig behavior. Relationships of measures of behavior with production traits were estimated. Traits chosen were backtest, resident-intruder, human approach (HAT), novel object (NOT), birth weight (BW), backfat depth (BF), loin muscle area (LMA), average daily gain in the farrowing house (ADGFH), average daily gain (ADG), 21 d weight (21DW), and 140 d weight (W). Each behavior trait was measured twice (n ≥ 457). The study consisted of 95 litters from 31 sires with an average of 3 sires per litter. Between 7 and 14 d of age the backtest was conducted by placing each pig in the supine position for 60 s. Total time spent struggling (TTS) and total number of attempts to struggle (TAS) were recorded. The resident-intruder test was performed in the nursery while the human approach (HAT) and novel object tests (NOT) were performed on the finishing floor. The resident intruder test involved two pigs; a resident pig and an intruder pig from another litter. The resident pen was divided in half with a solid door. One pig, a resident, was placed in the test area and an intruder pig was then introduced. Time taken until an attack occurred (LAT) and total number of attacks over the two tests (RIS) were recorded. Amount of time taken for each pig to make snout contact with an unfamiliar human (HAT) or object (NOT) was recorded. Dam and sire effects were significant for all traits (p < 0.01). Sex and pen effects were significant for LAT, RIS, HAT, and NOT (p < 0.10). Repeatabilities of TTS, TAS, RIS, LAT, HAT, and NOT were 0.38, 0.21, 0.07, 0.08, 0.17, 0.11, respectively. The phenotypic correlation between TTS and TAS was 0.61 and the phenotypic correlation between HAT and NOT was 0.34. The phenotypic relationship between RIS and LAT was -0.85. Total time spent struggling and TAS tended to be phenotypically correlated with 21DW and ADGFH. TAS was phenotypically correlated with BF (0.15). Latency until an attack occurred was phenotypically correlated with LMA (0.23). RIS was phenotypically correlated with ADG (-0.13), W (-0.13), and LMA (-0.21). Heritabilities of TTS and TAS were 0.31 and 0.53, respectively. Genetic correlation of TAS with both ADG and W was 0.38. Genetic correlations of TTS with BF, W, and TAS were 0.14, 0.18, and 0.81, respectively. It was concluded that the backtest is a heritable and repeatable measure of a behavioral characteristic in pigs that is both phenotypically and genetically correlated with performance.
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Griffin, Damian Gerard. "A family-based study investigating the genetic basis of calcium-containing kidney stones." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368068.
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Yazdansepas, Amir. "Studies of the stability, heritability, components and sub-components of harvest index in wheat." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq27474.pdf.
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