Academic literature on the topic 'Founder population'
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Journal articles on the topic "Founder population"
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CABALLERO, ARMANDO, and MIGUEL A. TORO. "Interrelations between effective population size and other pedigree tools for the management of conserved populations." Genetical Research 75, no. 3 (2000): 331–43. http://dx.doi.org/10.1017/s0016672399004449.
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Genetic parameters widely used to monitor genetic variation in conservation programmes, such as effective number of founders, founder genome equivalents and effective population size, are interrelated in terms of coancestries and variances of contributions from ancestors to descendants. A new parameter, the effective number of non-founders, is introduced to describe the relation between effective number of founders and founder genome equivalents. Practical recommendations for the maintenance of genetic variation in small captive populations are discussed. To maintain genetic diversity, minimum coancestry among individuals should be sought. This minimizes the variances of contributions from ancestors to descendants in all previous generations. The method of choice of parents and the system of mating should be independent of each other because a clear-cut recommendation cannot be given on the latter.
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Sölkner, J., L. Filipcic, and N. Hampshire. "Genetic variability of populations and similarity of subpopulations in Austrian cattle breeds determined by analysis of pedigrees." Animal Science 67, no. 2 (1998): 249–56. http://dx.doi.org/10.1017/s1357729800010006.
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AbstractParameters based on probabilities of gene origin were used to evaluate the genetic variability of four Austrian cattle breeds. Effective numbers of founders, ancestors and remaining founder genomes showed that all four populations investigated are rather small genetically. Effective numbers of remaining founder genomes were 94 for Simmental, 41 for Braunvieh (Brown Swiss), 32 for Pinzgauer and 21 for Grauvieh (Grey cattle, a small mountain breed). As the value of 94 for Simmental was rather large in comparison with estimates from other populations in previous studies, the effect of population structure was investigated. A cosine measure of similarity based on differences in individual founder contributions to different subpopulations was defined and used for analysis. Subpopulations defined by regions were clearly more distinct for Simmental than for Braunvieh. The size of the cosine values depended on the method of calculating founder contributions and was overestimated when choosing the method not accounting for drift and bottlenecks (effective number of founders).
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Montero-Pau, Javier, Africa Gómez, and Manuel Serra. "Founder effects drive the genetic structure of passively dispersed aquatic invertebrates." PeerJ 6 (December 11, 2018): e6094. http://dx.doi.org/10.7717/peerj.6094.
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Populations of passively dispersed organisms in continental aquatic habitats typically show high levels of neutral genetic differentiation despite their high dispersal capabilities. Several evolutionary factors, including founder events, local adaptation, and life cycle features such as high population growth rates and the presence of propagule banks, have been proposed to be responsible for this paradox. Here, we have modeled the colonization process to assess the impact of migration rate, population growth rate, population size, local adaptation and life-cycle features on the population genetic structure in these organisms. Our simulations show that the strongest effect on population structure are persistent founder effects, resulting from the interaction of a few population founders, high population growth rates, large population sizes and the presence of diapausing egg banks. In contrast, the role of local adaptation, genetic hitchhiking and migration is limited to small populations in these organisms. Our results indicate that local adaptation could have different impact on genetic structure in different groups of zooplankters.
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Gruber, Stephen B. "Population stratification in epidemiologic studies of founder populations." Cancer Biomarkers 3, no. 3 (2007): 123–28. http://dx.doi.org/10.3233/cbm-2007-3302.
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Wu, Jing Li. "A Practical Heuristic Algorithm for the Minimum Founder Set Reconstructive Problem." Advanced Materials Research 393-395 (November 2011): 549–54. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.549.
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It has been generally accepted that current-day population evolved from a small number of specific sequences called founders, and the genomic sequences (called recombinants) of individuals within the population are composed of segments from the founders due to recombination. In this paper, the minimum founder set problem is studied. A practical heuristic algorithm HMFS is presented for solving the problem, which partitions the sites of founders into three parts and reconstructs them respectively. Experimental results show that HMFS can solve the minimum founder set problem fast and effectively. Furthermore, when the number of recombinants and SNP sites grows large, HMFS is still able to find satisfied solution to this problem very quickly. Hence it is practical in realistic applications
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DeVries, Ashleigh, Deborah Budge, Terry Schwaner, and Delilah Schwaner. "Genetic variation in founder populations of the Mediterranean gecko, Hemidactylus turcicus, across the southern United States." Amphibia-Reptilia 29, no. 3 (2008): 438–42. http://dx.doi.org/10.1163/156853808785112084.
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Abstract Populations initially founded by a small number of individuals risk chance increases in some genetic variants and experience periods during which only a few individuals survive to continue the existence of the population. Colonization of new locations by individuals from these founder populations is expected to result in further reduction of variation in founding populations. Tissue samples from the Mediterranean gecko, Hemidactylus turcicus, were subjected to allozyme electrophoresis to measure gene frequencies at two polymorphic loci for populations initially introduced to port cities along the Gulf Coast, and which are now distributed across the southern United States. We observed levels of polymorphism and heterozygosity that were markedly reduced in populations more distant from coastal localities, consistent with a hypothesis of founder effect.
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Davis, Michelle L., Carl Barker, Ian Powell, Keith Porter, and Paul Ashton. "Combining modelling, field data and genetic variation to understand the post-reintroduction population genetics of the Marsh Fritillary butterfly (Euphydryas aurinia)." Journal of Insect Conservation 25, no. 5-6 (2021): 875–86. http://dx.doi.org/10.1007/s10841-021-00354-3.
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Abstract The Marsh Fritillary butterfly (Euphydryas aurinia) is a Eurasian species which has suffered significant reductions in occurrence and abundance over the past century, particularly across the western side of its range, due to agricultural intensification and habitat loss. This loss has been particularly severe in the UK with extensive localised extinctions. Following sympathetic management, reintroduction was undertaken at four Cumbria (northern UK) sites in 2007 with stock from a captive admixture population descended from Cumbrian and Scottish founders. Annual population monitoring of the reintroductions was undertaken. Nine years post-reintroduction, the level of population genetic variation was assessed using microsatellites. Variation in historical Cumbrian samples was determined using museum samples and Scottish samples from current populations were assayed to characterise natural population variation. Half of the Scottish sites also served as indicators of the alleles present in the founder populations. The genetic contribution of the founder populations allied to population size data allowed patterns of genetic variation to be modelled. Alleles from Cumbrian and Scottish founders are present in the reintroduced populations. The four sites have levels of variation akin to natural populations and exhibit differentiation as predicted by statistical modelling and comparable with natural populations. This suggests that reintroduction following captive breeding can produce self-sustaining populations with natural levels of genetic diversity. These populations appear to be undergoing the same evolutionary dynamics with bottlenecks and drift as natural populations. Implications for insect conservation Reintroduction of captive bred individuals is a viable strategy for producing populations with natural levels of genetic diversity and evolutionary dynamics. Hybridisation of populations on the brink of extinction with those thriving can preserve some of the genetic distinctiveness of the declining population.
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Viluma, Agnese, Øystein Flagstad, Mikael Åkesson, et al. "Whole-genome resequencing of temporally stratified samples reveals substantial loss of haplotype diversity in the highly inbred Scandinavian wolf population." Genome Research 32, no. 3 (2022): 449–58. http://dx.doi.org/10.1101/gr.276070.121.
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Genetic drift can dramatically change allele frequencies in small populations and lead to reduced levels of genetic diversity, including loss of segregating variants. However, there is a shortage of quantitative studies of how genetic diversity changes over time in natural populations, especially on genome-wide scales. Here, we analyzed whole-genome sequences from 76 wolves of a highly inbred Scandinavian population, founded by only one female and two males, sampled over a period of 30 yr. We obtained chromosome-level haplotypes of all three founders and found that 10%–24% of their diploid genomes had become lost after about 20 yr of inbreeding (which approximately corresponds to five generations). Lost haplotypes spanned large genomic regions, as expected from the amount of recombination during this limited time period. Altogether, 160,000 SNP alleles became lost from the population, which may include adaptive variants as well as wild-type alleles masking recessively deleterious alleles. Although not sampled, we could indirectly infer that the two male founders had megabase-sized runs of homozygosity and that all three founders showed significant haplotype sharing, meaning that there were on average only 4.2 unique haplotypes in the six copies of each autosome that the founders brought into the population. This violates the assumption of unrelated founder haplotypes often made in conservation and management of endangered species. Our study provides a novel view of how whole-genome resequencing of temporally stratified samples can be used to visualize and directly quantify the consequences of genetic drift in a small inbred population.
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Foote, Imogen, Stephanie S. Godfrey, and Bruce C. Robertson. "Mate choice explains high genetic diversity in a small founding population of the New Zealand sea lion (Phocarctos hookeri)." Australian Journal of Zoology 66, no. 6 (2018): 343. http://dx.doi.org/10.1071/zo19023.
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Founder populations are susceptible to reduced genetic diversity, which can hinder successful population establishment. A new genetic lineage of the New Zealand sea lion (Phocarctos hookeri) has recently colonised the historical range of the New Zealand mainland (Otago Peninsula). Despite a small founding population, previous research indicated that nuclear genetic diversity in the Otago Peninsula population is similar to that of the larger source population (Sandy Bay, Auckland Islands). Our research aimed to identify whether mechanisms of female mate choice could help to explain the unexpectedly high level of genetic diversity in the founder population. We used genetic data at 12 microsatellite loci for mother–pup pairs from both populations, and the software COLONY to identify putative paternal genotypes inferred from allele sharing between known mother–pup pairs. We found that mating pairs were, on average, more related at the Otago Peninsula location. However, Sandy Bay females were mating with males more related to themselves than expected by chance, while the Otago Peninsula females were not. These findings suggest that female choice in this otariid species appears important, although may be constrained in some situations. Our findings also help to explain how the recently founded population is able to maintain a viable, growing population.
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Karacaören, Burak. "Empirical comparison of association and admixture mapping for body weight using F<sub>2</sub> mice data set." Archives Animal Breeding 57, no. 1 (2014): 1–6. http://dx.doi.org/10.7482/0003-9438-57-005.
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Abstract. Recent advances in molecular genetics have provided hundreds of thousands of single nucleotide polymorphisms (SNPs) to detect mutations in genes related with complex traits. Undetected shared ancestry within samples of individuals could lead to the detection of false genomic signals in association mapping. Pedigree-based relationship matrices or genomic relationship matrices could be used in a mixed model to predict and correct for genetic stratifications. Genotypic information of founder populations could also be used to explore patterns of inheritance for complex traits by admixture mapping. An F2 population was created using M16 and ICR mouse lines for studying body weight at 8 weeks of age. Genotypes were collected for 1813 SNPs for each animal, including the founders. Bayesian residuals were used for population stratification in the admixture model. Association and admixture mapping detected similar genomic signals from chromosome 10. Our results provide empirical proof that gene flow from ancestral populations could be traced by admixture mapping with founder genotypes.
Dissertations / Theses on the topic "Founder population"
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黃冠萍 and Kwun-ping Flora Wong. "A study of MSH2 founder mutation in Hong Kong population." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41712316.
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Wong, Kwun-ping Flora. "A study of MSH2 founder mutation in Hong Kong population." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41712316.
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Väisänen, M. L. (Marja-Leena). "Fragile X syndrome in Northern Finland:molecular, diagnostic and population genetic aspects." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514253779.
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Abstract
Fragile X syndrome, the most common inherited form of mental retardation syndrome, is caused by an expansion of the CGG trinucleotide repeat in the 5' UTR of the FMR1 gene, with concurrent hypermethylation of the region, which represses FMR1 expression. The syndrome is associated with the folate-sensitive chromosomal fragile site at Xq27.3 (FRAXA), where the gene responsible for the syndrome was first localized by linkage analysis using RFLP markers. In this study the linkage relationships of the RFLP markersat Xq27-28 and the characteristics of the CGG repeat expansion were investigated in northern Finnish fragile X families and molecular diagnostic methods were applied in order to improve diagnosis of the syndrome. Furthermore, the origin of fragile X mutations in the northern part of Finland was studied by haplotype analysis.
Linkage studies were performed in 34 northern Finnish fragile X families/pedigrees using a total of 15 RFLPs (defining 11 loci). A refined genetic map around FRAXA including five RFLP markers having recombination fractions of 0.04 or less with FRAXA was obtained in an international study of 112 affected families, containing linkage data on twelve northern Finnish families. Linkage analysis significantly improved carrier detection in fragile X families compared with previous cytogenetic methods used in diagnosis. The most efficient RFLP-based protocol for carrier detection was proposed, which is based on use of the most adjacent markers and a minimum number of restriction enzymes.
CGG repeat expansion of the FMR1 gene was investigated in original families collected for linkage studies and additional new ones. Large CGG repeat expansions (Δ > 500 bp) with concomitant methylation of the adjacent CpG island, i.e. full mutations, were found to be associated with mental retardation completely in males, but only 50% of the females having a full mutation were mentally impaired. Premutations (Δ < 700 bp) were found in healthy carriers. There was a size range of Δ = 500 to 700 bp, where the expansions could be either abnormally methylated or non-methylated, and it appeared that methylation is more important in determining the phenotype than the exact size of an expansion. Instability of the enlarged CGG repeats was detected, leading preferentially to size increases in successive generations. The instability of premutations was found to be stronger and the size increases larger in maternal than in paternal transmissions, and transition to a full mutation occurred only in female transmissions. In addition, the size of a maternal premutation was shown to have an important influence on the risk of its transition to a full mutation when transmitted. The critical premutation size leading invariably to full mutation in the offspring was found to be between Δ = 175 to 200 bp. In one of the studied families a rare contraction of a paternal premutation to a normal CGG repeat number in one of the daughters and further in her son was detected. Direct mutation analysis including measurement of the CGG repeat size and hypermethylation allowed unambiguous diagnosis of carriers and affected individuals in most cases.
Haplotype analysis using two tightly linked microsatellite markers flanking the CGG repeat mutation was performed in 60 unrelated northern and eastern Finnish fragile X families. A significant difference was found in allelic and haplotypic distributions between normal X and fragile X chromosomes. A single haplotype, which was present only in 8% of the normal X chromosomes, accounted for 80% of the fragile X chromosomes. This enrichment of one fra(X) mutation in the Finnish population suggests founder effect.
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Roos, J. L. (Johannes Louw). "Genetic variation and clinical variables contributing to Schizophrenia in a Founder Population from South Africa." Thesis, University of Pretoria, 2014. http://hdl.handle.net/2263/44335.
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Thirty publications are submitted. They deal with findings of the genetic architecture of schizophrenia in an Afrikaner founder population and clinical related variables pertaining to this population.
The initial research findings supported the appropriateness of the Afrikaner population for mapping complex traits using both linkage and linkage disequilibrium (LD) approaches. Basic sample descriptors and cardinal symptoms of schizophrenia in the US and South African populations were equivalent. It was concluded that the results from our genetic study of schizophrenia in the Afrikaner sample will be applicable to other populations.
It was found that early non-psychotic childhood deviance (in the first ten years of life) distinguished a distinct subtype of schizophrenia patient, and that the form of early deviance manifested, was meaningful linked to later disease outcome; and that it may be a possible endophenotypic marker in schizophrenia but not in bipolar disorder.
Schizophrenia genetic research used linkage analysis, association studies and exome sequencing studies as it became available in the last few years. We addressed the role of the individual genes from the 22q11 locus (prototype CNV described in schizophrenia). Systematic screening of the 26 genes residing in this locus identified PRODH2, ZDHHC8, NOGO Receptor 1 (RTN4R) gene as contributing to schizophrenia risk associated with this region. Linkage genome-wide scans, using both less dense (10cM) and more dense scans (2cM), identified a locus on chromosome 1 and 13. Recent fine mapping on chromosome 13q32-34 and brain expression analysis implicates MYO16 in schizophrenia (not included in the 30 publications). For the first time a probound with a uniparental disomy (UPD) of the entire chromosome 1, was identified, which further support the involvement of chromosome 1 in schizophrenia.
We confirmed the previous reported rate of 2% frequency of 22q11 deletions in adult schizophrenia Afrikaner patients and provided a two-stage screening protocol to identify these patients in clinical practice. As more patients were recruited for this study certain comorbid conditions became obvious including marijuana use/abuse and obsessive compulsive disorder (OCD) and obsessive compulsive symptoms (OCS).
Approximately half of the male patients and a quarter of the female patients used or abused marijuana. Male users of marijuana with prominent early non-psychotic deviant behaviour in the first 10 years of life had the lowest mean age of criteria onset (18.4 years) with a poor prognosis. The prevalence of OCD/OCS in this population was 13.2% and differs from other ethnic groups in South Africa, and was associated with significant psychopathology and poor prognosis.
As the research progressed the emphasis has changed from familial cases with the disease to sporadic cases (non-familial). We offered the first clear view of the genetic landscape of schizophrenia. We found that rare de novo structural mutations at many different loci are significantly enriched and contribute to schizophrenia vulnerability in sporadic cases with the disease. We also demonstrated that genes contribute to familial schizophrenia, while new mutations are less prominent.
The study of schizophrenia in the Afrikaner founder population has helped to clear the view of the genetic landscape of schizophrenia.<br>Thesis (DSc)--University of Pretoria, 2014.<br>tm2015<br>Psychiatry<br>DSc<br>Unrestricted
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Kayim, Mehmet. "Founder Effect In Reintroduced Anatolian Mouflon Ovis Gmelinii Anatolica Valenciennes 1856 Populations." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610015/index.pdf.
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Reintroduction of Anatolian mouflon population at Bozdag Protection &<br>Breeding Station to its former habitats(Emremsultan Wildlife Development Area in Ankara-Nallihan, and Karadag in Karaman) started in 2004. The magnitude of genetic change among Bozdag and reintroduced populations was evaluated by 11 microsatellite loci. Study populations revealed close results (±<br>st.dev.) &ndash<br>Bozdag population: nk = 2.9091 (±<br>1.1362), AE = 2.0250 (±<br>0.9537), Ho = 0.3830 (±<br>0.2717), He = 0.3956 (±<br>0.2746)<br>Nallihan population: nk = 2.9091 (±<br>1.1362), AE = 2.0592 (±<br>0.9451), Ho = 0.4086 (±<br>0.2977), He = 0.4052 (±<br>0.2767)<br>and Karadag population: nk = 2.5455 (±<br>1.1282), AE = 1.8809 (±<br>0.8758), Ho = 0.3388 (±<br>0.2775), He = 0.3607 (±<br>0.2716). Population differences for major genetic parameters were not significant (p ><br>0.05) by comparisons with paired t-test. Also, temporal change in genetic diversity for Bozdag population was investigated by comparison with temporal data. Temporal changes in genetic parameters were found to be not significant and possible causes for differences were argued. Additionally, genetic diversity and PI computations for different traps were verified and compared to uncover any potential bias due to the catching method. Comparisons did not reveal significant differences illustrating the homogeneity among traps. On the other hand, simulations detected the higher sensitivity of allelic diversity (A) to founder events than P and heterozygosity (Ho &<br>He) levels which supports heterozygosity excess method for bottleneck analysis. With the same simulation analysis, observed genetic diversity within reintroduced samples were found to be in the ranges of expectation (99% CI) indicating that translocated individuals were chosen randomly. Bottleneck analysis based on heterozygosity excess method (one-tailed test for heterozygosity excess: pSMM = 0.28515, pTPM = 0.06445, pIAM = 0.02441) and allele frequency distributions method (normal L-shaped) could not detect a recent genetic bottleneck for Bozdag population. However, simulations determined that these two methods are prone to type II error. Bottleneck detection failure for the study population is probably due to type II error instead of other sources of error like violations of model assumptions.
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Paré, Guillaume. "Genetic analysis of 100 loci for coronary artery disease and associated phenotypes in a founder population." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99196.
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Coronary artery disease (CAD) is a major health concern for both developed and developing countries. With a heritability estimated at around 50%, there is a strong rationale to better define the genetic contribution of CAD. In order to do so, my thesis project consists in the genetic analysis of over 1400 individuals from the Saguenay Lac St-Jean region using 1536 single nucleotide polymorphisms in 103 candidate genes for CAD. Using this data, suggestive linkage for HDL cholesterol was found on chromosome 1 and several significant associations were observed with lipoprotein-related traits as well as adiponectin plasma concentration, including two novel associations.
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Wajiki, Yuichi. "Studies on Genetic Diversity and Its Maintenance in the Japanese Population of Japanese Crested Ibis (Nipponia nippon)." Kyoto University, 2016. http://hdl.handle.net/2433/215226.
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Cameron, Emilie C. "Fruit Fly Pests of Northwestern Australia." University of Sydney, 2007. http://hdl.handle.net/2123/1711.
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Doctor of Philosophy(PhD),<br>Until recently, Northwestern Australia was thought to be relatively free of serious fruit fly pests. Although a noxious strain, present in Darwin since 1985, was widely believed to be an infestation of the Queensland fruit fly, Bactrocera tryoni, from the East coast, the fruit flies present outside this area were believed to be the benign endemic species, B. aquilonis. However, during the year 2000, infestations of fruit flies were discovered on major commercial crops in both Western Australia and the Northern Territory. It was not known whether these outbreaks were due to an invasion of the major pest species, Bactrocera tryoni, a change in the behaviour of B. aquilonis, or a hybridisation event between the two species. Finding the source of these outbreaks has been complicated by the fact that, since B. tryoni and B. aquilonis are virtually indistinguishable morphologically, it was not known which species are present in the region. Traditionally any tryoni complex fly caught in the Northwest was called B. aquilonis based solely on location. In order to get a good population profile of the region, an extensive trapping program was set up to include flies from urban areas, commercial crops and natural areas where the benign strain is thought to remain. Tests of genetic differentiation and clustering analyses revealed a high degree of homogeneity in the Northwest samples, suggesting that just one species is present in the region. The Northwest samples were genetically differentiated from the Queensland samples but only to a small degree (FST =0.0153). MtDNA sequencing results also showed a small degree of differentiation between these regions. A morphological study of wing shape indicated that there are some minor identifiable morphological differences between East coast and Northwest laboratory reared flies. This difference was greater than that seen between B. jarvisi populations across the same geographic range. The results suggest that the flies caught in the Northwest are a separate population of B. tryoni. Soon after pest flies were discovered in Darwin, a population became established in Alice Springs. This population had a low genetic diversity compared with Queensland and Darwin populations, and showed evidence of being heavily founded. In 2000, an outbreak was discovered in the nearby town of Ti Tree. Due to the geographic and genetic similarity of these populations, Alice Springs was determined to be the source of the Ti Tree outbreak. To investigate the founding of these populations, a program was developed to estimate the propagule size. Using a simulation method seven different statistics were tested for estimating the propagule size of an outbreak population. For outbreaks originating from populations with high genetic diversity, the number of alleles was a good estimator of propagule size. When, however, the genetic diversity of the source population was already reduced, allele frequency measures, particularly the likelihood of obtaining the outbreak population from the source population, gave more accurate estimates. Applying this information to the Alice Springs samples, it was estimated that just five flies were needed to found the major population in and around Alice Springs. For Ti Tree, the propagule size was estimated to be 27 flies (minimum 10). In 2000, a much larger outbreak occurred in the developing horticultural region of Kununurra in northern Western Australia. An important question for the management of the problem is whether there is an established fly population or the flies are reinvading each year. This population was found to have a large amount of gene flow from the Northern Territory. Within the Kununurra samples, one group of flies was genetically differentiated from all the other samples. This group came from a small geographic area on the periphery of Kununurra and appeared to be the result of an invasion into this area at the time when the population was building up following the dry season. A further threat to the Northwest horticultural regions comes from B. jarvisi. A recent increase in the host range of this species has lead to speculation that it may become a greater pest in Northwestern Australia. At the present time, protocols for the population monitoring and disinfestation of this species are not in place. Here it is shown that B. jarvisi eggs are more heat tolerant than B. tryoni eggs and that monitoring of B. jarvisi populations is possible using cue lure traps placed according to fruiting time and location of their favoured host, Planchonia careya.
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Cameron, Emilie C. "Fruit Fly Pests of Northwestern Australia." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1711.
Full textAbstract:
Until recently, Northwestern Australia was thought to be relatively free of serious fruit fly pests. Although a noxious strain, present in Darwin since 1985, was widely believed to be an infestation of the Queensland fruit fly, Bactrocera tryoni, from the East coast, the fruit flies present outside this area were believed to be the benign endemic species, B. aquilonis. However, during the year 2000, infestations of fruit flies were discovered on major commercial crops in both Western Australia and the Northern Territory. It was not known whether these outbreaks were due to an invasion of the major pest species, Bactrocera tryoni, a change in the behaviour of B. aquilonis, or a hybridisation event between the two species. Finding the source of these outbreaks has been complicated by the fact that, since B. tryoni and B. aquilonis are virtually indistinguishable morphologically, it was not known which species are present in the region. Traditionally any tryoni complex fly caught in the Northwest was called B. aquilonis based solely on location. In order to get a good population profile of the region, an extensive trapping program was set up to include flies from urban areas, commercial crops and natural areas where the benign strain is thought to remain. Tests of genetic differentiation and clustering analyses revealed a high degree of homogeneity in the Northwest samples, suggesting that just one species is present in the region. The Northwest samples were genetically differentiated from the Queensland samples but only to a small degree (FST =0.0153). MtDNA sequencing results also showed a small degree of differentiation between these regions. A morphological study of wing shape indicated that there are some minor identifiable morphological differences between East coast and Northwest laboratory reared flies. This difference was greater than that seen between B. jarvisi populations across the same geographic range. The results suggest that the flies caught in the Northwest are a separate population of B. tryoni. Soon after pest flies were discovered in Darwin, a population became established in Alice Springs. This population had a low genetic diversity compared with Queensland and Darwin populations, and showed evidence of being heavily founded. In 2000, an outbreak was discovered in the nearby town of Ti Tree. Due to the geographic and genetic similarity of these populations, Alice Springs was determined to be the source of the Ti Tree outbreak. To investigate the founding of these populations, a program was developed to estimate the propagule size. Using a simulation method seven different statistics were tested for estimating the propagule size of an outbreak population. For outbreaks originating from populations with high genetic diversity, the number of alleles was a good estimator of propagule size. When, however, the genetic diversity of the source population was already reduced, allele frequency measures, particularly the likelihood of obtaining the outbreak population from the source population, gave more accurate estimates. Applying this information to the Alice Springs samples, it was estimated that just five flies were needed to found the major population in and around Alice Springs. For Ti Tree, the propagule size was estimated to be 27 flies (minimum 10). In 2000, a much larger outbreak occurred in the developing horticultural region of Kununurra in northern Western Australia. An important question for the management of the problem is whether there is an established fly population or the flies are reinvading each year. This population was found to have a large amount of gene flow from the Northern Territory. Within the Kununurra samples, one group of flies was genetically differentiated from all the other samples. This group came from a small geographic area on the periphery of Kununurra and appeared to be the result of an invasion into this area at the time when the population was building up following the dry season. A further threat to the Northwest horticultural regions comes from B. jarvisi. A recent increase in the host range of this species has lead to speculation that it may become a greater pest in Northwestern Australia. At the present time, protocols for the population monitoring and disinfestation of this species are not in place. Here it is shown that B. jarvisi eggs are more heat tolerant than B. tryoni eggs and that monitoring of B. jarvisi populations is possible using cue lure traps placed according to fruiting time and location of their favoured host, Planchonia careya.
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Broders, Hugh G. "Population genetic structure and the effect of founder events on the genetic variability of moose (Alces alces) in Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0035/MQ47418.pdf.
Full textBooks on the topic "Founder population"
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Stephan, Pelikan, ed. Genetic diversity in establishing plant populations: Founder number and geometry. Science Publishers ; Boca Raton, FL : Distributed by CRC Press, 2011.
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Kelleher, Mary Jane. Influence of parasitoids on a population of diplolepis splinosa (Ashmead) (Hymenoptera: Cynipidae) found on rosa rugosa thunb. (Rosaceae) in Sudbury, Ontario. s.n.], 1988.
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Hess, Elizabeth. Lost and found: Dogs, cats, and everyday heroes at a country animal shelter. Harcourt Brace, 1998.
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Bessolicyn, Aleksandr. Cinema of the Modern Era (Joint-stock cinematographic companies in Russia at the beginning of the twentieth century). INFRA-M Academic Publishing LLC., 2024. http://dx.doi.org/10.12737/2145830.
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Based on a wide range of sources, the monograph shows the activities of the main officially registered joint-stock cinematographic companies operating in Russia at the beginning of the twentieth century. Economic modernization, which flourished in Russia at the turn of the XIX – XX centuries, accelerated the process of formation of joint-stock cinematographic companies. This period turned out to be bright for Russia, but chronologically short. Having turned into a mass spectacle, cinema developed along the path of transformation into an art form that was technological in nature and focused largely on the broad masses of the population. This predetermined the interest of private business in this type of entertainment, which saw a real opportunity to make significant profits by involving democratic segments of the population, primarily cities, in this form of leisure activities. At the beginning of the twentieth century, branches of famous French film companies operated in Russia: Gaumont, Br Pathe, as well as about 20 officially registered domestic joint-stock companies, the largest of which was the joint-stock company A.A. Khanzhonkov and Co., which turned out to be the most effective in the pre-revolutionary film business. The paper examines the mechanism of approval of joint-stock cinematographic companies, the formation of management bodies and the participation of founders and shareholders in this process, as well as in the distribution of profits and payment of dividends.
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Rogstad, Steven H., and Stephan Pelikan. Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry. Taylor & Francis Group, 2011.
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Rogstad, Steven H., and Stephan Pelikan. Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry. Taylor & Francis Group, 2011.
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Brisbane, Arthur. What Mrs. Eddy Said To Arthur Brisbane: The Celebrated Interview Of The Eminent Journalist With The Discoverer And Founder Of Christian Science. Kessinger Publishing, LLC, 2006.
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Kay, Chris, Emily Fisher, and Michael R. Hayden. Epidemiology. Oxford University Press, 2014. http://dx.doi.org/10.1093/med/9780199929146.003.0007.
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The prevalence and persistence of Huntington’s disease (HD) is crucially informed by the causative mutation. Diagnostic and predictive testing has enabled a new era of epidemiologic study of HD, whereby only those who carry an expanded CAG repeat are included in such measures. In Western populations, estimated prevalence of the disease is higher following the introduction of genetic testing, and prevalence may also be increasing in absolute terms. There are worldwide differences in the prevalence of HD by ethnicity and population, which may be accounted for in part by genetic diversity of the CAG repeat and the surrounding haplotype. HD is endemic to all populations, but is most common in populations of European ancestry in which specific disease haplotypes are found. New mutations maintain HD in a population, and genetic differences by population may contribute to differences in the de novo mutation rate.
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Anselmi, A. C. M., S. C. E. Gallon, P. Müller, and K. Reinhardt. Populationsgröße, Trichterdichte und Habitatpräferenz der Dünen-Ameisenjungfer Myrmeleon bore (Tjeder, 1941) im Gebiet der Dresdner Heide (Neuroptera). Technische Universität Dresden, 2021. http://dx.doi.org/10.25368/2022.402.
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Following the first record of Myrmeleon bore (Tjeder, 1941) in the Dresden Heath area in 2019 (KURTH 2020, Sächs. Entomol. Z. 10: 71-80), the population size and density of the species was determined. M. bore mainly was found in open, sparsely vegetated, sandy areas with direct sunlight exposure. The area-weighted density of the entire study site (4.05 hectares) was 0.177 larvae/m2. Population size estimates based on random quadrat counts lead to a figure of 4000-7000 individuals - the largest known population of this species. The positive correlation between larval size and pit diameter known for this species from laboratory trials was confirmed at our study site. This correlation may allow researchers to estimate the age structure of wild populations. Given the special responsibility of Germany for the protection of this species and the size of the population, we urge the protection of the site and a prioritisation over other protected species found in the area.
Book chapters on the topic "Founder population"
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Lim, Lisa. "Yesterday’s founder population, today’s Englishes." In Varieties of English Around the World. John Benjamins Publishing Company, 2014. http://dx.doi.org/10.1075/veaw.g49.23lim.
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Tremblay, Marc, Hélène Vézina, Bertrand Desjardins, and Louis Houde. "Distant Kinship and Founder Effects in the Quebec Population." In Kinship and Demographic Behavior in the Past. Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6733-4_12.
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Heyde, C. C. "On the Survival of a Gene Represented in a Founder Population." In Selected Works of C.C. Heyde. Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-5823-5_46.
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Albrecht, Matthew A., and Joyce Maschinski. "Influence of Founder Population Size, Propagule Stages, and Life History on the Survival of Reintroduced Plant Populations." In Plant Reintroduction in a Changing Climate. Island Press/Center for Resource Economics, 2012. http://dx.doi.org/10.5822/978-1-61091-183-2_10.
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McCalman, Janet, Leonard Smith, Sandra Silcot, and Rebecca Kippen. "Building a Life Course Dataset from Australian Convict Records: Founders & Survivors: Australian Life Courses in Historical Context, 1803–1920." In Population Reconstruction. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19884-2_14.
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Fontdevila, A. "Founder Effects in Colonizing Populations: The Case of Drosophila buzzatii." In Evolutionary Biology of Transient Unstable Populations. Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74525-6_6.
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Drew, Richard A. I., and Meredith C. Romig. "Species and speciation." In The fruit fly fauna (Diptera: Tephritideae: Dacinae) of Papua New Guinea, Indonesian Papua, Associated Islands and Bougainville. CABI, 2022. http://dx.doi.org/10.1079/9781789249514.0004.
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Abstract This chapter discusses two species models, which are diametrically opposed. The first, often called the 'biological species concept', defines species in terms of 'reproductive isolation', convinced that species arise when subsets of a population are split off and remain geographically isolated over evolutionary time. If and when such new species are reunited with their founder population, interbreeding does not occur, or if it does, infertile progeny result. Hence, from the biological species concept, natural selection is a primary agent of change and directly selects for new species. In this sense, species are the direct products of natural selection and they are therefore 'adaptive devices'. When applying this species concept, it has been impossible to separate some sibling species of fruit flies in the genus Bactrocera where distinct morphological species can be similar in molecular analyses of certain DNA sequences, while similar species morphologically are distinct in the same molecular characters. A radically different model, the 'recognition concept of species', relies heavily on a knowledge of species ecology and behaviour, particularly in their natural habitat. The principal points in this concept are given. In contrast to the now-outdated biological species concept that leads one to depend on laboratory-based research to define species, the recognition concept requires workers to undertake extensive field research in the habitat of the taxon under investigation. In translating this approach to research in the insect family Tephritidae, particularly the Dacinae, some 35 years of field surveys have been undertaken throughout the Indian subcontinent, South-east Asia and the South Pacific region. These surveys included trapping using male lure traps and host fruit collections of commercial/edible fruits. The results of this work have included the provision of specimens of almost all known species for morphological descriptions (c.800 species), material for male pheromone chemistry, and data on host fruit relationships and biogeographical studies.
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Ekanem, Jemimah Timothy, and Idongesit Michael Umoh. "Social Vulnerability of Rural Dwellers to Climate Variability: Akwa Ibom State, Nigeria." In African Handbook of Climate Change Adaptation. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_232.
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AbstractFor their livelihood activities, rural farming communities depend more on extractive capital. Their capacity to cultivate sufficiently for their family maintenance is greatly impeded by the absence of either temperature or rainfall quantity pattern or uniformity. The divergent effects of recent extreme weather events around the world, including within relatively small geographical areas, exemplify the unequal impacts of climate change on populations. Akwa Ibom State has been found vulnerable to extreme weather events, such as flooding, severe storms, and rising sea levels, leading to homelessness, poverty, conflicts, and war for millions of people. All of these have resulted in social disturbances and dislocations among rural populations, especially in coastal communities, making them more vulnerable to climate variability. In the field of social vulnerability in the state, not much has been achieved. This chapter analyzes the vulnerability of the rural population to climate variability; the socio-economic characteristics of the rural population; the index of social vulnerability of rural dwellers to climate variability; social vulnerability factors; and the rural population’s social vulnerability mitigation initiatives in Akwa Ibom State, Nigeria. Social science approaches to human vulnerability draw critical attention to the root causes and factors why people are forced to respond to risks from climate change. A complex social approach to vulnerability is most likely to enhance mitigation and adaptation preparation efforts, given that vulnerability is a multidimensional mechanism rather than an invariable state.
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Ekanem, Jemimah Timothy, and Idongesit Michael Umoh. "Social Vulnerability of Rural Dwellers to Climate Variability: Akwa Ibom State, Nigeria." In African Handbook of Climate Change Adaptation. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-42091-8_232-1.
Full textAbstract:
AbstractFor their livelihood activities, rural farming communities depend more on extractive capital. Their capacity to cultivate sufficiently for their family maintenance is greatly impeded by the absence of either temperature or rainfall quantity pattern or uniformity. The divergent effects of recent extreme weather events around the world, including within relatively small geographical areas, exemplify the unequal impacts of climate change on populations. Akwa Ibom State has been found vulnerable to extreme weather events, such as flooding, severe storms, and rising sea levels, leading to homelessness, poverty, conflicts, and war for millions of people. All of these have resulted in social disturbances and dislocations among rural populations, especially in coastal communities, making them more vulnerable to climate variability. In the field of social vulnerability in the state, not much has been achieved. This chapter analyzes the vulnerability of the rural population to climate variability; the socio-economic characteristics of the rural population; the index of social vulnerability of rural dwellers to climate variability; social vulnerability factors; and the rural population’s social vulnerability mitigation initiatives in Akwa Ibom State, Nigeria. Social science approaches to human vulnerability draw critical attention to the root causes and factors why people are forced to respond to risks from climate change. A complex social approach to vulnerability is most likely to enhance mitigation and adaptation preparation efforts, given that vulnerability is a multidimensional mechanism rather than an invariable state.
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Poortman, Anne-Rigt. "Postdivorce Parent-Child Contact and Child Outcomes: The Role of Spatial Mobility." In European Studies of Population. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68479-2_10.
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AbstractShared physical custody, or more generally, frequent contact with both parents is often assumed to benefit children, but having to move back and forth between parents’ homes may also be harmful, particularly when parents live far apart. This study examined the role of spatial mobility in the association between frequent parent-child contact and multiple child outcomes. Using the New Families in the Netherlands survey, analyses firstly showed that frequent parent-child contact, on average, was found to be not or modestly associated with better child outcomes. Second, spatial mobility mattered, but in varying ways. Long travel times were negatively associated with children’s contact with friends and their psychological well-being, but positively related to educational performance. Furthermore, frequent commutes were negatively associated with how often children saw their friends, but positively associated with child psychological well-being. Third, and most importantly, the impact of parent-child contact and frequent commutes on child outcomes were found to be dependent on traveling time. For child psychological well-being and contact with friends, frequent parent-child contact and/or frequent commutes were found to have positive effects when travel distances were short, but these positive effects disappeared when traveling times increased.
Conference papers on the topic "Founder population"
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Larsen, Jan, Torben Lund Skovhus, Aaron Marc Saunders, Bo Højris, and Mikkel Agerbæk. "Molecular Identification of MIC Bacteria from Scale and Produced Water: Similarities and Differences." In CORROSION 2008. NACE International, 2008. https://doi.org/10.5006/c2008-08652.
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Abstract Culture-based methods of traditional microbiology applied to microbiological processes involved in reservoir souring and microbiologically influenced corrosion (MIC) pose a risk of yielding inadequate or contradictory results. Therefore, the industry calls for more accurate and faster techniques. The need for in-situ cultivation-independent methods has over the past ten years facilitated the development of several analytical methods for determination of bacterial identity, quantity, and to some extent function, applied directly to samples of the native population. This development has so far been limited regarding practical application and it has only recently been transferred to the oil industry. We have applied state-of-the-art molecular tools to monitor progressive corrosion attacks in an offshore oil facility in the Danish sector of the North Sea. We investigated the similarities and differences among MIC bacterial populations obtained from produced water and bacteria found in corrosion spots in a X-mas tree from a producing well. Molecular methods proved to be a powerful tool in identifying the involved microorganisms and the most likely corrosion process. The entire population of bacteria found in the corrosion deposit was characterised and found to consist almost entirely of sulfate reducing bacteria (SRB), of which the critical species were identified. Additionally, we determined that the bacterial populations that are present in the produced water are somewhat different to those found in the corrosion deposit. Many of the bacteria in the produced water are involved in souring processes and the production of H2S. Future research is focussing on the development of a direct and rapid method to specifically measure the critical SRB involved in MIC, both in deposits but also as a routine monitoring tool in the produced water. This new and improved microbiological approach is an important criterion in designing and testing remedial actions towards reservoir souring and MIC.
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Geissler, Brett. "Identification of Compounds That Effectively Block Microbial H2S Production." In CORROSION 2017. NACE International, 2017. https://doi.org/10.5006/c2017-09551.
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Abstract Microbial reduction of sulfur compounds is a concern in many industries due to the toxicity and corrosivity of the chief metabolic waste product, hydrogen sulfide (H2S). In the oil and gas industry, production of H2S by microbes within the petroleum reservoir is extremely detrimental to production and often leads to complete shut-in of wells and entire assets due to these concerns. Hundreds of different genera of bacteria and archaea are capable of generating H2S from an array of sulfur-containing compounds, although the key enzymes involved are relatively well conserved. We have identified a class of inhibitory molecules that abrogate sulfidogenesis by numerous diverse microbial populations found within oilfield produced fluids. Using bottle tests and laboratory-scale bioreactors designed to more closely mimic field conditions, very low doses of two different versions of this class of compounds were found to effectively prevent H2S generation and decrease the number of sulfide-producing microbes from the population. Although not proven experimentally, by decreasing the amount of H2S generated, these compounds will likely be able to decrease the levels of microbiologically influenced corrosion normally associated with sulfidogenic populations of microbes.
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Park, Hyung Soo, Jaspreet Mand, Thomas R. Jack, and Gerrit Voordouw. "Microbial Community Composition and MIC in Water Systems for Bitumen Production by SAGD." In CORROSION 2013. NACE International, 2013. https://doi.org/10.5006/c2013-02768.
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Abstract Internal corrosion risk exists in the pipeline systems and treatment facilities supplying water from the subsurface to steam-generating facilities in Steam Assisted Gravity Drainage (SAGD) operations. The waters contain high concentrations of bicarbonate, and some sulfate, but no nitrate. Water treatment includes addition of sodium bisulfite (SBS), as an oxygen scavenger. Samples were obtained from a source well and water treatment facility upstream and downstream of the SBS injection point. The planktonic microbial community was found to change significantly through the system. Exposure of steel coupons to CO2-containing synthetic oilfield brine in the laboratory resulted in the rapid development of biofilm populations rich in methanogenic Archaea. These organisms are increasingly being recognized as agents of microbially influenced corrosion (MIC). Addition of SBS in the water treatment process promoted a microbial population able to ferment added sulfite into sulfate and sulfide or sulfur, all of which have the potential to cause further corrosion problems downstream through the action of sulfate reducing bacteria and/or through the deposition of elemental sulfur on exposed steel surfaces. The observations reported here support previous work on brackish water facilities in the same site.
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Larsen, Jan, Torben Lund Skovhus, Mikkel Agerbæk, Trine Rolighed Thomsen, and Per Halkjær Nielsen. "Bacterial Diversity Study Applying Novel Molecular Methods on Halfdan Produced Waters." In CORROSION 2006. NACE International, 2006. https://doi.org/10.5006/c2006-06668.
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Abstract Nitrate has been added to the injection water in the Halfdan field since January 2001 in order to prevent reservoir souring. In early 2005, seawater breakthrough had occurred in four wells on Halfdan, and nitrate breakthrough was also detected. This resulted in a shift to nitrate utilizing bacteria in the produced water, confirming the impact of nitrate and the need to continuously monitor and optimize the treatment. In this paper we demonstrate that key bacterial populations can be identified by applying a range of novel molecular methods. Molecular techniques were implemented on water samples from Halfdan production wells producing with and without seawater breakthrough. For bacterial quantification, fluorescence in situ hybridization (FISH) was applied using a range of 8 hybridization probes. In order to describe the bacterial community composition in further detail a combination of molecular techniques was used. These techniques included polymerase chain reaction (PCR) followed by denaturing gradient gel electrophoresis (DGGE) and direct gene sequencing. In addition, gel retardation studies specifically targeting the genetic sequence coding for dissimilatory sulfite reduction (dsrAB) were conducted, thereby creating a fingerprint of both sulfate reducing Bacteria and sulfate reducing Archaea. The results demonstrated that reliable cell counts could be obtained using the FISH technique in Halfdan produced waters. DGGE could be applied directly on these waters, giving unique and different gel patterns between the monitored wells. The identity of the most abundant microbes in the produced waters could be determined using a direct gene sequencing method. In all wells the Gammaproteobacteria were dominant, and Halomonas–related bacteria were present. Also, Thermococcus-related microorganisms belonging to the Archaea were present in all wells. Presence of other bacteria was unique for the different wells reflecting the different production histories. Gel retardation on the dsrAB gene showed presence of sulfate reducing bacteria (SRB) in all wells, although the population structure was different. In most wells a low diversity in the microbial population was found.
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Al-Humam, Abdulmohsen A., Tony Y. Rizk, Jan A. Sunner, and Iwona B. Beech. "Effects of Nitrate on Bacterial Communities in an Oil Field Environment." In CORROSION 2010. NACE International, 2010. https://doi.org/10.5006/c2010-10249.
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Abstract The study aimed to determine whether nitrate-utilizing sulfate-reducing bacteria (SRB) thrive in the Hawtah oil field produced water re-injection system (PWRI). Bacterial populations were recovered through enrichments in selective growth media from samples collected at different locations in PWRI. Characterization of purified Hawtah field SRB isolates using 16S rRNA gene-based phylogeny, revealed the presence of an isolate, coded DD-H SRB, showing a high 16S rRNA sequence similarity (99%) with Desulfovibrio desulfuricans spp. desulfuricans. The change from sulfate to nitrate reduction was tested using the DD-H SRB isolate and a “wild” Hawtah SRB enrichment in the laboratory batch culture experiments. Control culture comprised a tri-species mixture of pure Desulfovibrio strains. Both, the DD-H SRB isolate and the control SRB culture, when exposed to a gradually decreasing concentration of sulfate and a concurrently increasing concentration of nitrate over a 40-day period, changed slowly from sulfate to nitrate respiration. Upon inoculation into a sulfate-free medium, fast nitrate reduction was observed. In the “wild” Hawtah field SRB population, the transition to nitrate reduction was faster. The functional gene aprA, coding for adenosine-5-phosphosulfate (APS)-reductase enzyme, which is found in all known SRB genera, was present in all tested cultures grown with nitrate as a sole electron acceptor.
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Oparaodu, Kingsley, and Ibiba Braide. "Microbiological Profiles and Risk Exposures in Topside Production Systems of FPSOs in West Africa." In CONFERENCE 2022. AMPP, 2022. https://doi.org/10.5006/c2022-18017.
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Abstract Microbiological risk evaluation of topside systems of four floating production storage and offloading in West Africa was carried out over a period of four years. Field samples were taken, and DNA analyzed using next-generation sequencing technology to identify and classify the microbial population present on the facilities. Several classes of bacteria and archaea were sequenced and identified from the samples, including those that have been shown to play key roles in biofouling, microbiologically influenced corrosion and biogenic hydrogen sulphide generation in oil and gas production systems. The classic microbial population according to metabolic classes associated with oil and gas production systems were identified. The study found that of the 137 microbial genera identified, 45.3% were associated with biofouling, 29.9% with microbiologically influenced corrosion, 29.1% with a H2S/MIC risk and a 2.9% population did not have a clear link to any of these risks. There was at least 98% relative abundance of bacteria population in the samples from all FPSOs, implying a significant exposure to the risks posed by microbial growth and proliferation.
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Walsh, Daniel, Merlin Danford, and Qiu Qiong. "The Corrosion Resistance of Aluminum 2219-T87 to Dilute Biologically Active Solutions." In CORROSION 1992. NACE International, 1992. https://doi.org/10.5006/c1992-92166.
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Aluminum 2219-T87 samples were exposed to biologically active agents found in Environmental Control and Life Support System (ECLSS) hygiene waste water. Corrosive attack was correlated to alloy composition and microstructure, the electrochemistry of the fluid media, and to the microbial population found in the hygiene water.
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Yao, Tsung-Chieh, Caroline A. Motika, Lucille Lester, and Carole Ober. "A Genome-Wide Association Study Of Lung Function In A Founder Population." In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a1348.
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Scholand, Mary Beth, Roger Wolff, Hilary Coon, et al. "Founder Effects In Interstitial Pulmonary Fibrosis: A Population Based Analysis Over Four Centuries." In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a5525.
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Alvarez, Rosa M., Jose Velazquez, Veronica Fragoso, et al. "Abstract 4278: Screening for BRCA1 founder mutation in Mexican population: an accessible approach." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-4278.
Full textReports on the topic "Founder population"
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Fridman, Eyal, Jianming Yu, and Rivka Elbaum. Combining diversity within Sorghum bicolor for genomic and fine mapping of intra-allelic interactions underlying heterosis. United States Department of Agriculture, 2012. http://dx.doi.org/10.32747/2012.7597925.bard.
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Heterosis, the enigmatic phenomenon in which whole genome heterozygous hybrids demonstrate superior fitness compared to their homozygous parents, is the main cornerstone of modern crop plant breeding. One explanation for this non-additive inheritance of hybrids is interaction of alleles within the same locus. This proposal aims at screening, identifying and investigating heterosis trait loci (HTL) for different yield traits by implementing a novel integrated mapping approach in Sorghum bicolor as a model for other crop plants. Originally, the general goal of this research was to perform a genetic dissection of heterosis in a diallel built from a set of Sorghum bicolor inbred lines. This was conducted by implementing a novel computational algorithm which aims at associating between specific heterozygosity found among hybrids with heterotic variation for different agronomic traits. The initial goals of the research are: (i) Perform genotype by sequencing (GBS) of the founder lines (ii) To evaluate the heterotic variation found in the diallel by performing field trails and measurements in the field (iii) To perform QTL analysis for identifying heterotic trait loci (HTL) (iv) to validate candidate HTL by testing the quantitative mode of inheritance in F2 populations, and (v) To identify candidate HTL in NAM founder lines and fine map these loci by test-cross selected RIL derived from these founders. The genetic mapping was initially achieved with app. 100 SSR markers, and later the founder lines were genotyped by sequencing. In addition to the original proposed research we have added two additional populations that were utilized to further develop the HTL mapping approach; (1) A diallel of budding yeast (Saccharomyces cerevisiae) that was tested for heterosis of doubling time, and (2) a recombinant inbred line population of Sorghum bicolor that allowed testing in the field and in more depth the contribution of heterosis to plant height, as well as to achieve novel simulation for predicting dominant and additive effects in tightly linked loci on pseudooverdominance. There are several conclusions relevant to crop plants in general and to sorghum breeding and biology in particular: (i) heterosis for reproductive (1), vegetative (2) and metabolic phenotypes is predominantly achieved via dominance complementation. (ii) most loci that seems to be inherited as overdominant are in fact achieving superior phenotype of the heterozygous due to linkage in repulsion, namely by pseudooverdominant mechanism. Our computer simulations show that such repulsion linkage could influence QTL detection and estimation of effect in segregating populations. (iii) A new height QTL (qHT7.1) was identified near the genomic region harboring the known auxin transporter Dw3 in sorghum, and its genetic dissection in RIL population demonstrated that it affects both the upper and lower parts of the plant, whereas Dw3 affects only the part below the flag leaf. (iv) HTL mapping for grain nitrogen content in sorghum grains has identified several candidate genes that regulate this trait, including several putative nitrate transporters and a transcription factor belonging to the no-apical meristem (NAC)-like large gene family. This activity was combined with another BARD-funded project in which several de-novo mutants in this gene were identified for functional analysis.
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Gur, Amit, Edward Buckler, Joseph Burger, Yaakov Tadmor, and Iftach Klapp. Characterization of genetic variation and yield heterosis in Cucumis melo. United States Department of Agriculture, 2016. http://dx.doi.org/10.32747/2016.7600047.bard.
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Project objectives: 1) Characterization of variation for yield heterosis in melon using Half-Diallele (HDA) design. 2) Development and implementation of image-based yield phenotyping in melon. 3) Characterization of genetic, epigenetic and transcriptional variation across 25 founder lines and selected hybrids. The epigentic part of this objective was modified during the course of the project: instead of characterization of chromatin structure in a single melon line through genome-wide mapping of nucleosomes using MNase-seq approach, we took advantage of rapid advancements in single-molecule sequencing and shifted the focus to Nanoporelong-read sequencing of all 25 founder lines. This analysis provides invaluable information on genome-wide structural variation across our diversity 4) Integrated analyses and development of prediction models Agricultural heterosis relates to hybrids that outperform their inbred parents for yield. First generation (F1) hybrids are produced in many crop species and it is estimated that heterosis increases yield by 15-30% globally. Melon (Cucumismelo) is an economically important species of The Cucurbitaceae family and is among the most important fleshy fruits for fresh consumption Worldwide. The major goal of this project was to explore the patterns and magnitude of yield heterosis in melon and link it to whole genome sequence variation. A core subset of 25 diverse lines was selected from the Newe-Yaar melon diversity panel for whole-genome re-sequencing (WGS) and test-crosses, to produce structured half-diallele design of 300 F1 hybrids (MelHDA25). Yield variation was measured in replicated yield trials at the whole-plant and at the rootstock levels (through a common-scion grafted experiments), across the F1s and parental lines. As part of this project we also developed an algorithmic pipeline for detection and yield estimation of melons from aerial-images, towards future implementation of such high throughput, cost-effective method for remote yield evaluation in open-field melons. We found extensive, highly heritable root-derived yield variation across the diallele population that was characterized by prominent best-parent heterosis (BPH), where hybrids rootstocks outperformed their parents by 38% and 56 % under optimal irrigation and drought- stress, respectively. Through integration of the genotypic data (~4,000,000 SNPs) and yield analyses we show that root-derived hybrids yield is independent of parental genetic distance. However, we mapped novel root-derived yield QTLs through genome-wide association (GWA) analysis and a multi-QTLs model explained more than 45% of the hybrids yield variation, providing a potential route for marker-assisted hybrid rootstock breeding. Four selected hybrid rootstocks are further studied under multiple scion varieties and their validated positive effect on yield performance is now leading to ongoing evaluation of their commercial potential. On the genomic level, this project resulted in 3 layers of data: 1) whole-genome short-read Illumina sequencing (30X) of the 25 founder lines provided us with 25 genome alignments and high-density melon HapMap that is already shown to be an effective resource for QTL annotation and candidate gene analysis in melon. 2) fast advancements in long-read single-molecule sequencing allowed us to shift focus towards this technology and generate ~50X Nanoporesequencing of the 25 founders which in combination with the short-read data now enable de novo assembly of the 25 genomes that will soon lead to construction of the first melon pan-genome. 3) Transcriptomic (3' RNA-Seq) analysis of several selected hybrids and their parents provide preliminary information on differentially expressed genes that can be further used to explain the root-derived yield variation. Taken together, this project expanded our view on yield heterosis in melon with novel specific insights on root-derived yield heterosis. To our knowledge, thus far this is the largest systematic genetic analysis of rootstock effects on yield heterosis in cucurbits or any other crop plant, and our results are now translated into potential breeding applications. The genomic resources that were developed as part of this project are putting melon in the forefront of genomic research and will continue to be useful tool for the cucurbits community in years to come.
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D'Amore, Danny M. Behavioural syndrome, but not invasive syndrome, found in hybrid Xiphophorus helleri populations. Peeref, 2022. http://dx.doi.org/10.54985/peeref.2206p9523996.
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Winkler, Richelle (Richelle L. )., and Miranda H. Mockrin. Aging and wildfire risk to communities. U.S. Department of Agriculture, Economic Research Service, 2025. https://doi.org/10.32747/2025.9015828.ers.
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The population of the United States is aging as the Baby Boom generation grows older. In 2020, 23 percent of the U.S. population had reached age 60. The share of the population at older ages is forecast to increase to 26 percent in 2030 and 29 percent in 2050. Wildfire risks are also increasing, and older populations are especially vulnerable. This report found that most (87 percent) of the recent population growth in places with moderate-to-high wildfire risk has been among people over the age of 60. Already, the proportion of older people living in places with more wildfire risk is higher than in the population at large. In rural areas with the greatest wildfire risk, 35 percent of people living in those areas are over the age of 60. The number of older people exposed to wildfire risk is expected to increase as populations grow older and as wildfire increases in frequency and intensity.--
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Foulkee, William D. Locating a Prostate Cancer Susceptibility Gene on the X Chromosome by Linkage Disequilibrium Mapping Using Three Founder Populations in Quebec and Switzerland. Defense Technical Information Center, 2005. http://dx.doi.org/10.21236/ada443199.
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Foulkes, William D. Locating a Prostate Cancer Susceptibility Gene on the X Chromosome by Linkage Disequilibrium Mapping Using Three Founder Populations in Quebec and Switzerland. Defense Technical Information Center, 2002. http://dx.doi.org/10.21236/ada405914.
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Foulkes, William D. Locating a Prostate Cancer Susceptibility Gene on the X Chromosome by Linkage Disequilibrium Mapping Using Three Founder Populations in Quebec and Switzerland. Defense Technical Information Center, 2003. http://dx.doi.org/10.21236/ada415657.
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Foulkes, William D. Locating a Prostate Cancer Susceptibility Gene on the X Chromosome by Linkage Disequilibrium Mapping Using Three Founder Populationin Quebec and Switzerland. Defense Technical Information Center, 2004. http://dx.doi.org/10.21236/ada426100.
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Granath Hansson, Anna, and Hjördís Guðmundsdóttir. Remote Work in Smaller Towns: Possibilities and uncertainties. Nordregio, 2024. http://dx.doi.org/10.6027/r2024:51403-2503.
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Has remote work post-pandemic expanded the influence of Nordic capitals on surrounding towns? Through case studies in five Nordic towns, the report focused on how remote work opportunities influence small-town attractiveness, population retention, and planning strategies. It explores the effects on populations, urban-rural landscapes, and planning needs. The findings reveal a shift in population dynamics, with people moving from capitals to smaller towns, leveraging remote work's flexibility. This shift presents opportunities and challenges for regional development, highlighting the need for further research to navigate the complexities of remote work's long-term implications. Despite remote work becoming common, the study found little proof that remote work opportunities have made these towns more attractive. Remote or hybrid work can attract new populations and highly qualified personnel, enhancing towns' attractiveness without necessarily increasing the population. Ongoing research is needed to fully understand remote work's potential and inform policy and planning to attract new residents and visitors.
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Breiman, Adina, Jan Dvorak, Abraham Korol, and Eduard Akhunov. Population Genomics and Association Mapping of Disease Resistance Genes in Israeli Populations of Wild Relatives of Wheat, Triticum dicoccoides and Aegilops speltoides. United States Department of Agriculture, 2011. http://dx.doi.org/10.32747/2011.7697121.bard.
Full textAbstract:
Wheat is the most widely grown crop on earth, together with rice it is second to maize in total global tonnage. One of the emerging threats to wheat is stripe (yellow) rust, especially in North Africa, West and Central Asia and North America. The most efficient way to control plant diseases is to introduce disease resistant genes. However, the pathogens can overcome rapidly the effectiveness of these genes when they are wildly used. Therefore, there is a constant need to find new resistance genes to replace the non-effective genes. The resistance gene pool in the cultivated wheat is depleted and there is a need to find new genes in the wild relative of wheat. Wild emmer (Triticum dicoccoides) the progenitor of the cultivated wheat can serve as valuable gene pool for breeding for disease resistance. Transferring of novel genes into elite cultivars is highly facilitated by the availability of information of their chromosomal location. Therefore, our goals in this study was to find stripe rust resistant and susceptible genotypes in Israeli T. dicoccoides population, genotype them using state of the art genotyping methods and to find association between genetic markers and stripe rust resistance. We have screened 129 accessions from our collection of wild emmer wheat for resistance to three isolates of stripe rust. About 30% of the accessions were resistant to one or more isolates, 50% susceptible, and the rest displayed intermediate response. The accessions were genotyped with Illumina'sInfinium assay which consists of 9K single nucleotide polymorphism (SNP) markers. About 13% (1179) of the SNPs were polymorphic in the wild emmer population. Cluster analysis based on SNP diversity has shown that there are two main groups in the wild population. A big cluster probably belongs to the Horanum ssp. and a small cluster of the Judaicum ssp. In order to avoid population structure bias, the Judaicum spp. was removed from the association analysis. In the remaining group of genotypes, linkage disequilibrium (LD) measured along the chromosomes decayed rapidly within one centimorgan. This is the first time when such analysis is conducted on a genome wide level in wild emmer. Such a rapid decay in LD level, quite unexpected for a selfer, was not observed in cultivated wheat collection. It indicates that wild emmer populations are highly suitable for association studies yielding a better resolution than association studies in cultivated wheat or genetic mapping in bi-parental populations. Significant association was found between an SNP marker located in the distal region of chromosome arm 1BL and resistance to one of the isolates. This region is not known in the literature to bear a stripe rust resistance gene. Therefore, there may be a new stripe rust resistance gene in this locus. With the current fast increase of wheat genome sequence data, genome wide association analysis becomes a feasible task and efficient strategy for searching novel genes in wild emmer wheat. In this study, we have shown that the wild emmer gene pool is a valuable source for new stripe rust resistance genes that can protect the cultivated wheat.