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Journal articles on the topic 'Genetic diversity and divergence'
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1
Vajda, I., and J. Zvárová. "On Genetic Information, Diversity and Distance." Methods of Information in Medicine 45, no. 02 (2006): 173–79. http://dx.doi.org/10.1055/s-0038-1634063.
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Summary Objectives: General information-theoretic concepts such as f-divergence, f-information and f-entropy are applied to the genetic models where genes are characterized by randomly distributed alleles. The paper thus presents an information-theoretic background for measuring genetic distances between populations, genetic information in various observations on individuals about their alleles and, finally, genetic diversities in various populations. Methods: Genetic distances were derived as divergences between frequencies of alleles representing a gene in two different populations. Genetic information was derived as a measure of statistical association between the observations taken on individuals and the alleles of these individuals. Genetic diversities were derived from divergences and information. Results: The concept of genetic f-information introduced in the paper seems to be new. We show that the measures of genetic distance and diversity used in the previous literature are special cases of the genetic f-divergence and f-diversity introduced in the paper and illustrated by examples. We also display intimate connections between the genetic f-information and the genetic f-divergence on one side and genetic f-diversity on the other side. The examples at the same time also illustrate practical computations and applications of the important concepts of quantitative genetics introduced in the paper. Conclusions: We discussed a general class of f-divergence measures that are suitable measures of genetic distance between populations characterized by concrete frequencies of alleles. We have shown that a wide class of genetic information, called f-information, can be obtained from f-divergences and that a wide class of measures of genetic diversity, called f-diversities, can be obtained from the f-divergences and f-information.
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GONÇALVES, Viviane Pereira, Francisco Laurimar do Nascimento ANDRADE, Rafaelle Fazzi GOMES, and Lucas da Silva SANTOS. "Genetic diversity in creole genotypes of Amazon chicory." Acta Amazonica 52, no. 2 (April 2022): 89–95. http://dx.doi.org/10.1590/1809-4392202102852.
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ABSTRACT Amazon chicory is still a little-known vegetable despite its great agronomic potential. The characterization of chicory genotypes concerning genetic divergence is a key step for breeding programs, as it allows the selection of superior individuals and to explore the variability and complementarity of characteristics via interbreeding between newly generated genotypes. In this context, this study aimed to evaluate the genetic divergence among Amazon chicory creole genotypes from the northern Brazilian states of Pará and Rondônia based on morpho-agronomic traits. We conducted an experiment in a randomized block design with eight chicory genotypes (treatments) and four replications. Both quantitative and qualitative characteristics were evaluated. Genetic divergence was estimated via squared generalized Mahalanobis distance (D2), considering only quantitative characters, and the genotypes were subsequently clustered via the UPGMA method. Analysis of variance showed significant differences among genotypes for all studied characteristics, except shoot fresh weight. The UPGMA grouped the genotypes into three clusters, which demonstrated that the genotypes from Colares and Santarém Novo (Pará) (Chic-02 and Chic-04) were the most divergent as compared to the genotypes from Castanhal and Santa Isabel do Pará (Pará). Qualitative characteristics showed a monomorphic behavior and, therefore, were not used to assess genetic divergences. To obtain segregating populations with complementary characteristics, crossbreeding between the two most divergent clusters is recommended.
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MADHUMATHI, C., D. SRINIVASA REDDY, and B. HARI VARA PRASAD. "Genetic diversity in muskmelon (Cucumis melo)." Indian Journal of Agricultural Sciences 90, no. 5 (September 4, 2020): 934–37. http://dx.doi.org/10.56093/ijas.v90i5.104364.
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The present investigation was carried out during 2014-15 and 2015–16 at Horticultural Research Station, Ananthrajupet, DRYSRHU, Andhra Pradesh to assess the genetic diversity in muskmelon, Cucumis melo. Genetic divergence evaluated using Mahalanobis D2 analysis revealed less to moderate diversity among fourty two genotypes. The cluster analysis of muskmelon exhibited a moderate clustering pattern and grouped genotypes into five distinct clusters with maximum of 37 genotypes in cluster I, two in cluster IV and one in each of cluster II, III and V. The highest inter-cluster distance (80.61) between Cluster III and IV indicating the genotypes of these clusters may give heterotic response and leads to better segregants. Among the morphological traits studied, fruit length (23.69%), pulp thickness (17.07%) and fruit girth (16.84%) contributed major share in the divergence of the genotypes which can be utilized for selection of individual genotypes for future crop improvement programme. Most of the genotypes accommodated into single cluster, probably they may share genetic similarity. The genotypes Papayee S-1, IC 321371, Kundan, Muskan and Arka Jeet, being divergent from others may serve as potential parents for breeding programmes.
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Mariz, Joana, Ricardo Franco-Duarte, Fernanda Cássio, Cláudia Pascoal, and Isabel Fernandes. "Aquatic Hyphomycete Taxonomic Relatedness Translates into Lower Genetic Divergence of the Nitrate Reductase Gene." Journal of Fungi 7, no. 12 (December 11, 2021): 1066. http://dx.doi.org/10.3390/jof7121066.
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Aquatic hyphomycetes are key microbial decomposers in freshwater that are capable of producing extracellular enzymes targeting complex molecules of leaf litter, thus, being crucial to nutrient cycling in these ecosystems. These fungi are also able to assimilate nutrients (e.g., nitrogen) from stream water, immobilizing these nutrients in the decomposing leaf litter and increasing its nutritional value for higher trophic levels. Evaluating the aquatic hyphomycete functional genetic diversity is, thus, pivotal to understanding the potential impacts of biodiversity loss on nutrient cycling in freshwater. In this work, the inter- and intraspecific taxonomic (ITS1-5.8S-ITS2 region) and functional (nitrate reductase gene) diversity of 40 aquatic hyphomycete strains, belonging to 23 species, was evaluated. A positive correlation was found between the taxonomic and nitrate reductase gene divergences. Interestingly, some cases challenged this trend: Dactylella cylindrospora (Orbiliomycetes) and Thelonectria rubi (Sordariomycetes), which were phylogenetically identical but highly divergent regarding the nitrate reductase gene; and Collembolispora barbata (incertae sedis) and Tetracladium apiense (Leotiomycetes), which exhibited moderate taxonomic divergence but no divergence in the nitrate reductase gene. Additionally, Tricladium chaetocladium (Leotiomycetes) strains were phylogenetically identical but displayed a degree of nitrate reductase gene divergence above the average for the interspecific level. Overall, both inter- and intraspecific functional diversity were observed among aquatic hyphomycetes.
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N., Swami Naidu, Ghosh S.K., and Kokkanti Mallikarjuna. "Heterosis in relation to genetic diversity in pearl millet (Pennisetum glaucum L.)." Annals of Plant Sciences 7, no. 2 (January 31, 2018): 2016. http://dx.doi.org/10.21746/aps.2018.7.2.6.
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In the advent of failure of some transgenics at the field level and concerns due to biosafety and bioethical issues, there much thrust on natural plant genetic diversity as a means of adaptive value. Plant breeding basing on natural genetic diversity has gained momentum along with marker assisted breeding technologies for increased production and sustenance to various kinds of stresses. In the present investigation, divergence classification (DC) – a method devised by Arunachalam and Bandyopadhyay (1984) were used to classify 28 Pearl millet genotypes to draw a limit of parental diversity in expressing maximum heterosis. Mahalanobis D2 (D2 Values) statistic was used to measure the genetic diversity and then the genotypes were classified in to four divergence classes based on mean and standard deviation of all D2 values. According to divergence classification DCI involved most distantly and DCIV the most closely related parents where as DCII and DCIII involved the medium divergent parents. A scoring system was adopted to work out the relative order of importance of the divergence classes. The overall scores for each divergence classes based on the proportion of crosses (q) showing significant heterosis (heterosis over better parent) in desired direction and mean (y) of such crosses for ten characters were carried out to rank the divergence classes. According to the scoring system, the most desirable class would be with the lowest total score. Results clearly showed the superiority of class DCIII followed by DCII, as both the classes received low overall score and maximum number of heterotic cross combinations. In conclusion it can be said that divergence classification appears to be effective in clubbing the pearl millet genotypes for parental diversity and suggested that pearl millet parents with intermediate diversity would be used to produce heterotic cross combination.
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Hood, Glen R., Andrew A. Forbes, Thomas H. Q. Powell, Scott P. Egan, Gabriela Hamerlinck, James J. Smith, and Jeffrey L. Feder. "Sequential divergence and the multiplicative origin of community diversity." Proceedings of the National Academy of Sciences 112, no. 44 (October 23, 2015): E5980—E5989. http://dx.doi.org/10.1073/pnas.1424717112.
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Phenotypic and genetic variation in one species can influence the composition of interacting organisms within communities and across ecosystems. As a result, the divergence of one species may not be an isolated process, as the origin of one taxon could create new niche opportunities for other species to exploit, leading to the genesis of many new taxa in a process termed “sequential divergence.” Here, we test for such a multiplicative effect of sequential divergence in a community of host-specific parasitoid wasps, Diachasma alloeum, Utetes canaliculatus, and Diachasmimorpha mellea (Hymenoptera: Braconidae), that attack Rhagoletis pomonella fruit flies (Diptera: Tephritidae). Flies in the R. pomonella species complex radiated by sympatrically shifting and ecologically adapting to new host plants, the most recent example being the apple-infesting host race of R. pomonella formed via a host plant shift from hawthorn-infesting flies within the last 160 y. Using population genetics, field-based behavioral observations, host fruit odor discrimination assays, and analyses of life history timing, we show that the same host-related ecological selection pressures that differentially adapt and reproductively isolate Rhagoletis to their respective host plants (host-associated differences in the timing of adult eclosion, host fruit odor preference and avoidance behaviors, and mating site fidelity) cascade through the ecosystem and induce host-associated genetic divergence for each of the three members of the parasitoid community. Thus, divergent selection at lower trophic levels can potentially multiplicatively and rapidly amplify biodiversity at higher levels on an ecological time scale, which may sequentially contribute to the rich diversity of life.
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Bindroo, Bharat Bhusan, and Shunmugam Manthira Moorthy. "Genetic Divergence, Implication of Diversity, and Conservation of Silkworm, Bombyx mori." International Journal of Biodiversity 2014 (May 13, 2014): 1–15. http://dx.doi.org/10.1155/2014/564850.
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Genetic diversity is critical to success in any crop breeding and it provides information about the quantum of genetic divergence and serves a platform for specific breeding objectives. It is one of the three forms of biodiversity recognized by the World Conservation Union (IUCN) as deserving conservation. Silkworm Bombyx mori, an economically important insect, reported to be domesticated over 5000 years ago by human to meet his requirements. Genetic diversity is a particular concern because greater genetic uniformity in silkworm can increase vulnerability to pests and diseases. Hence, maintenance of genetic diversity is a fundamental component in long-term management strategies for genetic improvement of silkworm which is cultivated by millions of people around the worlds for its lusture silk. In this paper genetic diversity studies carried out in silkworm using divergent methods (quantitative traits and biochemical and molecular markers) and present level of diversity and factors responsible for loss of diversity are discussed.
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ALMEIDA, ADRIANA QUEIROZ DE, SIMONE ALVES SILVA, VANESSA DE OLIVEIRA ALMEIDA, DEOCLIDES RICARDO DE SOUZA, and GILMARA DE MELO ARAÚJO. "GENETIC DIVERGENCE AND MORPHO-AGRONOMIC PERFORMANCE OF JATROPHA CURCAS L. CLONES FOR SELECTION OF CLONAL VARIETIES." Revista Caatinga 29, no. 4 (December 2016): 841–49. http://dx.doi.org/10.1590/1983-21252016v29n408rc.
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ABSTRACT The knowledge about genetic diversity of jatropha crop is important for genetic conservation resources and breeding of this species. The aim of this study was to evaluate the genetic diversity and performance of jatropha clones through morphological characterization to selection of clonal varieties for biofuels production. The clones were obtained through shoot cuttings from previous selection in a population of half-sibs progenies. The morphoagronomic analyses of clones was carried out at 180 days after transplantation and were evaluated plant height, stem diameter, number of primary branches and number of secondary branches, number of bunches and number of fruits per plant. Evaluating clones performance, significant results were found for the number of secondary branches. About analysis of genetic diversity, the measures of dissimilarity genetic varied from 0.62 to 13.11, this way, the UFRBPR14 and UFRBPR15 clones were more divergent. The Tocher method was efficient to verify formation of four groups. The characteristics that most contributed to the divergence among clones were branches number, height and number of bunches, and, stem diameter had lower contribution. The jatropha clones differed only in the secondary branches number and multivariate analysis showed divergence among the jatropha clones with formation of four groups. Also, branches number, plant height and number of bunches were characteristic that contributed to genetic divergence.
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Hegde, Ramakrishna, and Mohan Varghese. "Genetic divergence analysis in Eucalyptus camaldulensis Dehnh." Indian Journal of Forestry 31, no. 1 (March 1, 2008): 61–66. http://dx.doi.org/10.54207/bsmps1000-2008-jz69n7.
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Eucalyptus camaldulensis Dehnh. is one of the important tree species used in modern plantation forestry programme. The genetic divergence analysis helps in assessing the genetic diversity within the species and also provide information for developing breeding plan, establishment of seed orchards and exploitation of heterosis through hybridization. In the present study attempts were made to assess the genetic diversity among the different open pollinated families of E. camaldulensis based on growth parameters at 24 months of age in three different locations.
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Nuryanto, Agus, Dian Baghawati, Kusbiyanto Kusbiyanto, Moh Husein Sastranegara, and Farida Nur Rachmawati. "Molecular Characterization of Anguilla from Cibereum and Sapuregel Rivers Segara Anakan Watersheds Cilacap, Central Java." Biogenesis: Jurnal Ilmiah Biologi 8, no. 2 (December 30, 2020): 145. http://dx.doi.org/10.24252/bio.v8i2.15532.
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The taxonomic status of Anguilla species' in river watershed that empties into Segara Anakan Cilacap is uncertain, thereby making it difficult for further studies to be carried out to determine its genetic in that area. Therefore, this study evaluates Anguilla's taxonomic status and population genetic in Cibeureum and Sapuregel River watersheds. Data were obtained from molecular characterization study using cytochrome c oxidase 1, with fourteen Anguilla specimens collected from two sequenced watersheds. Taxonomic status was determined based on homology and divergence values and monophyly of the samples to the reference species. Meanwhile, genetic divergences among samples to the reference species were calculated based on the Juke-Cantor substitution model in DnaSP6. A homology test was performed using a basic local alignment search tool, with monophyly inferred from the cladogram, which was developed using neighbor-joining and maximum likelihood algorithms in MEGAX with 1000 pseudoreplicates and out-group comparison. Furthermore, population genetic was analyzed through polymorphism, haplotype, nucleotide diversity within the population, divergence, and genetic differences. All calculations conducted in Arlequin 3.5 had Anguilla samples comprising of high (99.23% to 99.84%) to low genetic divergences (0.224% to 1.127%). The result shows that cladogram with all Anguilla samples formed a monophyletic clade with A. bicolor, separated from their taxa. Furthermore, Anguilla samples from both watersheds have low genetic polymorphisms with medium to high haplotype and nucleotide diversity. The population's comparison proved that both populations have low genetic divergence, and no genetic difference based on variance analysis (p=0761). Therefore, Anguilla resources in river watersheds that empty into Segara Anakan are a single genetic conservation unit.
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Maia, Maria Clideana Cabral, Mirian Fernandes Carvalho Araújo, Lucio Borges de Araújo, Carlos Tadeu dos Santos Dias, Luís Cláudio de Oliveira, Cosme Damião Cruz, Lúcio Flavio Lopes Vasconcelos, Luciano Medina Macedo, Gilberto Ken Iti Yokomizo, and Paulo Sarmanho da Costa Lima. "Genetic Divergence Among a Breeding Population of Hancornia Speciosa Gomes (Mangabeira) as Determined by Multivariate Statistical Methods." European Scientific Journal, ESJ 14, no. 15 (May 31, 2018): 421. http://dx.doi.org/10.19044/esj.2018.v14n15p421.
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The mangabeira its figure out among the mains native fruit tree explored by extractivism in Brasil. The objective evaluate the genetic divergence of landraces in orientation of crosses using multivariate techinics. The complete random blocks experimental design with four repetitions was used to evaluate twelve quantitative characteristics from twelve genotypes elite of mangabeiras concerning to divergence genetic using the software R (2012). Three groups genetically divergent were composed by biplot graphic and stored by UPGMA cluster analysis (Unweighted Pair-Group Method using Arithmetic Average / Weighted Clustering Method not using the Arithmetic Mean) showing genetic diversity and variability among 12 mangabeira accesses. Forty-four possible crosses are planned among genotypes of genetically dissimilar three groups and six among individuals in group III. Multivariate techniques were appropriate in the study of genetic divergence.
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Rahman, M., M. Hasan, R. N. Chowdhury, N. A. Ivy, and M. M. Hossain. "GENETIC DIVERSITY IN VEGETABLE PEA (Pisum sativum L.)." Bangladesh Journal of Plant Breeding and Genetics 26, no. 1 (June 30, 2013): 35–40. http://dx.doi.org/10.3329/bjpbg.v26i1.19982.
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An investigation was carried out to identify the extent of genetic divergence of seventeen vegetable pea genotypes at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Genetic divergence was estimated using D2 and principal component analysis. The genotypes under study fell into 4 clusters. The distribution pattern indicated that the maximum numbers of genotypes (6) were included in cluster II and cluster III and the minimum number in cluster IV (1). The inter-cluster distance was higher than the intra-cluster distance which indicated wider genetic diversity among the accessions of different groups. The highest inter-cluster distance was observed between II and IV. The lowest inter-cluster distance was observed between clusters II and III suggesting a close relationship among the genotypes of these two clusters. The highest intra-cluster distance was observed for the cluster II. The positive values of vector I and vector II for plant height, 50% flowering and non-reducing sugar indicated that these characters had the highest contribution towards the divergence among the pea genotypes. The genotypes of vegetable pea from cluster II and cluster IV maybe selected as parents in future hybridization program.DOI: http://dx.doi.org/10.3329/bjpbg.v26i1.19982
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Ricardo Manuel, Bardales-Lozano, Edvan Alves Chagas, Oscar Smiderle, Abanto-Rodriguez Carlos, Pollyana Cardoso Chagas, Adamor Barbosa Mota Filho, Olisson Mesquita Souza, and Antonio Carlos Centeno Cordeiro. "Genetic Divergence among Camu-Camu Plant Populations Based on the Initial Characteristics of the Plants." Journal of Agricultural Science 8, no. 11 (October 11, 2016): 51. http://dx.doi.org/10.5539/jas.v8n11p51.
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<p>The objective in the present work was to evaluate the genetic diversity among 15 indigenous populations of camu-camu plants, identifying important characteristics in the evaluation of genetic divergence, based on the initial characteristics of the seedlings. Seeds extracted from fruits deriving from fifteen indigenous populations of camu-camu were collected. The experimental design was entirely random, with fifteen treatments (populations), and fifteen repetitions (each sub-sample), considering 30 seeds per subsample as an experimental unit. At 40 days after sowing the following were evaluated: the percentage of emergence, the index of emergence velocity, the average time of germination, the height of the seedling and the number of leaves. The data obtained was submitted to variance analysis, and the averages were grouped by the Scott and Knott (1974) test. The genetic diversity was studied according to the Tocher grouping method, based on the Mahalanobis distance (D<sup>2</sup><sub>ii</sub>) and canonical variables. The fifteen populations are divergent among themselves and the Rio Branco Estirão do Veado, Rio Branco Onofre and Igarapé Agua Boa populations are indicated to have hybridization with other populations due to the high divergence, as well as the rates of emergence and vigor of the seedlings. The height of the seedlings, percentage and speed of emergence, are those that most indicate genetic divergence. The measuring techniques of genetic divergence, canonical variables Mahalanobis distances are useful and corroborating in the evaluation of genetic divergence of the camu-camu plant.</p>
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Servant, Annabelle, Syria Laperche, Francis Lallemand, Valérie Marinho, Guillemette De Saint Maur, Jean François Meritet, and Antoine Garbarg-Chenon. "Genetic Diversity within Human Erythroviruses: Identification of Three Genotypes." Journal of Virology 76, no. 18 (September 15, 2002): 9124–34. http://dx.doi.org/10.1128/jvi.76.18.9124-9134.2002.
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ABSTRACT B19 virus is a human virus belonging to the genus Erythrovirus. The genetic diversity among B19 virus isolates has been reported to be very low, with less than 2% nucleotide divergence in the whole genome sequence. We have previously reported the isolation of a human erythrovirus isolate, termed V9, whose sequence was markedly distinct (>11% nucleotide divergence) from that of B19 virus. To date, the V9 isolate remains the unique representative of a new variant in the genus Erythrovirus, and its taxonomic position is unclear. We report here the isolation of 11 V9-related viruses. A prospective study conducted in France between 1999 and 2001 indicates that V9-related viruses actually circulate at a significant frequency (11.4%) along with B19 viruses. Analysis of the nearly full-length genome sequence of one V9-related isolate (D91.1) indicates that the D91.1 sequence clusters together with but is notably distant from the V9 sequence (5.3% divergence) and is distantly related to B19 virus sequences (13.8 to 14.2% divergence). Additional phylogenetic analysis of partial sequences from the V9-related isolates combined with erythrovirus sequences available in GenBank indicates that the erythrovirus group is more diverse than thought previously and can be divided into three well-individualized genotypes, with B19 viruses corresponding to genotype 1 and V9-related viruses being distributed into genotypes 2 and 3.
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Rabbani, M. G., U. A. Naher, S. Pramanik, and M. K. Quais. "GENETIC DIVERSITY OF ASH GOURD (Benincasa hispida) GENOTYPES." Bangladesh Journal of Plant Breeding and Genetics 26, no. 2 (June 24, 2015): 01–08. http://dx.doi.org/10.3329/bjpbg.v26i2.23842.
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An experiment was conducted to study the field performance, variability and genetic divergence for yield and yield contributing characters of 46 ash gourd genotypes at the Horticulture Farm, Bangladesh Agricultural University, Mymensingh. Wide range of variations were found among the ash gourd genotypes in respect of different parameters such as vine length at harvest, fruit length, fruit diameter, sex ratio, number of fruits plant-1, average weight fruit-1 and yield plant-1. The genotype BH21 showed the highest performance in number of fruits plant-1 and yield plant-1. In respect of average weight fruit-1, the genotype BH16 produced the heaviest (1.86 kg) fruit and the genotype BHl7 produced the lightest (0.67 kg) fruit. The genotype BH18 had the highest sex ratio (8.16) and the genotype BH14 had the lowest sex ratio (3.44). In case of number of fruits plant-1, the genotype BH46 and BH53 had the minimum number of fruits (1.33) and the genotype BH21 had the maximum number of fruits (16.16) per plant which was statistically similar with the genotype BH12 (15.00). The genotypes were also tested for genetic divergence utilizing the multivariate analysis. The genotypes were grouped into eight clusters. However, there was no relationship found between genetic divergence and geographic distribution of the genotypes.
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SOBRAL, KAMILA MARCELINO BRITO, MANOEL ABÍLIO DE QUEIROZ, CARLOS ALBERTO DA SILVA LEDO, CARINA MENDES LOIOLA, JÉSSICA BARROS ANDRADE, and SEMÍRAMIS RABELO RAMALHO RAMOS. "GENETIC DIVERSITY ASSESSMENT AMONG TALL COCONUT PALM." Revista Caatinga 31, no. 1 (March 2018): 28–39. http://dx.doi.org/10.1590/1983-21252018v31n104rc.
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ABSTRACT The tall coconut (Cocos nucifera L.) has great socioeconomic importance in Brazil and was first introduced on the coast of the north-eastern region, where it has been exploited in a semi-extractivist manner. The goal of this study was to quantify the genetic divergence between accessions introduced and preserved at the International Coconut Genebank for Latin America and the Caribbean, estimate the efficiency of descriptors used in the discrimination of the accessions, and indicate the essential descriptors for the activities of characterisation and evaluation. The accessions used were: Polynesia Tall; Tonga Tall; West African Tall; Rennel Tall; Rotuma Tall; Vanuatu Tall; Malayan Tall and Brazilian Tall Praia-do-Forte. Thirty-five quantitative descriptors recommended for the species were used. Genetic divergence was estimated by the Mahalanobis’s generalised distance and the cluster analysis was performed using the unweighted pair group method with arithmetic mean (UPGMA). The relative importance of the descriptors was measured according to Singh and Jolliffe’s methods, and the variables were selected taking into consideration the matching information in the two methods, eliminating those that were discarded in the two procedures. The agronomic characteristics indicated that the first canonical variable explained 90.25% of total variance. The most efficient descriptors for detecting the genetic divergence were: fruit equatorial circumference; nut polar and equatorial circumference; quantity of liquid endosperm; total fruit weight; nut weight; stem height; girth of stem at 1,5m height; number of leaflets; and number of bunches. The most dissimilar accessions according to the agronomic characteristics were Rotuma Tall and West African Tall, which can be primarily indicated as genitors for the formation of segregating populations in breeding programmes.
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Majewski, Jacek, and Frederick M. Cohan. "Adapt Globally, Act Locally: The Effect of Selective Sweeps on Bacterial Sequence Diversity." Genetics 152, no. 4 (August 1, 1999): 1459–74. http://dx.doi.org/10.1093/genetics/152.4.1459.
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Abstract Previous studies have shown that genetic exchange in bacteria is too rare to prevent neutral sequence divergence between ecological populations. That is, despite genetic exchange, each population should diverge into its own DNA sequence-similarity cluster. In those studies, each selective sweep was limited to acting within a single ecological population. Here we postulate the existence of globally adaptive mutations, which may confer a selective advantage to all ecological populations constituting a metapopulation. Such adaptations cause global selective sweeps, which purge the divergence both within and between populations. We found that the effect of recurrent global selective sweeps on neutral sequence divergence is highly dependent on the mechanism of genetic exchange. Global selective sweeps can prevent populations from reaching high levels of neutral sequence divergence, but they cannot cause two populations to become identical in neutral sequence characters. The model supports the earlier conclusion that each ecological population of bacteria should form its own distinct DNA sequence-similarity cluster.
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Chetariya, C. P., and M. A. Vaddoria. "Genetic divergence analysis in bottle gourd [Lagenaria siceraria (Mol.) Standl.]." Journal of Applied and Natural Science 9, no. 4 (December 1, 2017): 1949–53. http://dx.doi.org/10.31018/jans.v9i4.1470.
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The study was conducted during summer 2014-15 at the Instructional Farm, College of Agriculture, Junagadh Agricultural University, Junagadh to assess the genetic diversity among 50 genotypes of bottle gourd (Ligenaria siceraria L.). The genetic diversity analysis revealed the formation of 13 clusters suggesting the presence of wide genetic diversity. The clustering pattern indicated that geographic diversity was not associated with genetic diversity. The analysis of per cent contribution of various characters towards the expression of total genetic divergence indicated that number of fruits per vine (22.45%) followed by number of primary branches per vine (13.80%), average fruit weight (11.51%), vine length (11.18%), fruit yield per vine (10.61%), number of male flowers (7.84%), fruit length (6.45%), ratio of male to female flowers (4.82%), days to first picking (4.49%) and days to opening of first male flower (3.84%) contributed maximum towards total genetic divergence. Based on the maximum genetic distance. It is advisable to attempt crossing of the genotypes from cluster XII(GP-14) with the genotypes of cluster IV (GP-25) and XI (GP-53), which may lead to the generation of broad spectrum of favourable genetic variability for yield improvement in bottle gourd.
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Arya, Pooja, and Suresh Kumar Maurya. "Assessment of genetic divergence in pumpkin (Cucurbita moschata)." Indian Journal of Agricultural Sciences 92, no. 6 (February 17, 2022): 726–31. http://dx.doi.org/10.56093/ijas.v92i6.110246.
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Pumpkin (Cucurbita moschata L.) is one of the most important Cucurbitaceous crops having a huge potential ofnutritional security and has vast diversity in Indian condition. Forty diverse genotypes of pumpkin were evaluated for phenotypical variations and assessment of genetic diversity, at G B Pant University of Agriculture and Technology Pantnagar during spring-summer of 2018 and 2019. The experiment was laid out in Randomized Block Design (RBD) with three replications. The data was subjected to Principal Component Analysis, where a total of 8 components were identified. First four components account for about 60.26% and 60.33% cumulative effects during first and second season, respectively. During first year the Eigen root of the first principal component caused 20.24% variation of total variation while, during second year the Eigen root of first principal component accounted 25.58% variation of total variation. A relative positive weight by each of the component to each single trait indicated that there was great scope for improvement in these traits through selection. Presence of sufficient phenotypic and genotypic diversity showed the scope in pumpkin crop for further improvement.
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Fortunato, Flávia Laís Gomes, Elizanilda Ramalho Do Rêgo, Michelle Gonçalves De Carvalho, Cristine Agrine Pereira Dos Santos, and Mailson Monteiro Do Rêgo. "Genetic diversity in ornamental pepper plants." Comunicata Scientiae 10, no. 3 (November 1, 2019): 364–75. http://dx.doi.org/10.14295/cs.v10i3.2843.
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The genus Capsicum comprises a wide variety of peppers and peppers, with different sizes, colors and flavors. The present work had the objective to characterize and evaluate the genetic divergence among eight accessions of pepper (Capsicum annuum). The experiment was developed at the Federal University of Paraíba, Areia - PB. Eight accessions of pepper belonging to the germplasm bank of the CCA-UFPB were used. The experimental design was completely randomized. Data were submitted to analysis of variance by the F test at a level of 5% and 1% significance and the means were grouped by the Scott Knott test at 5% and 1% significance. For the analysis of genetic divergence, the Tocher grouping method and canonical variables were used. The treatment effects were significant, by the F test, at a level of 1% for all the characteristics evaluated, except for crown width and stem diameter, which were significant at 5% probability. According to the results obtained in the Scott & Knott test at 5% and 1% probability, the accessions were differentiated into two to six different classes. According to Tocher’s methodology the accessions were grouped into two groups. In the analysis of the canonical variables, the first three variables explained 94.18% of the total variance, and four different groups were formed according to the graphical dispersion.
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Valadares, Ricardo N., Roberto A. Melo, Isabel VF Sarinho, Natália S. Oliveira, Fernando AT Rocha, José W. Silva, and Dimas Menezes. "Genetic diversity in accessions of melon belonging to momordica group." Horticultura Brasileira 36, no. 2 (June 2018): 253–58. http://dx.doi.org/10.1590/s0102-053620180218.
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ABSTRACT The genetic divergence of melon genotypes belonging to momordica group, collected in five Brazilian States, was estimated, and the relative contribution of the morphological characters was determined for the genetic variability. The experimental design was randomized blocks, with four replicates. We evaluated 19 accessions of melon, momordica group, two accessions of cantaloupensis group and two commercial cultivars of inodorus group. These genotypes were characterized by 42 morphological descriptors. The data were submitted to Tocher and UPGMA grouping methods using the genetic dissimilarity matrix, using Mahalanobis’ distance. Singh criterion was used to identify the relative contribution of each character to the genetic divergence. Four groups of similarity were obtained in both multivariate techniques, with agreement between hierarchical UPGMA and Tocher grouping methods. The characters: pistil scar size, soluble solid content, seed length, fruit length and cotyledon length contributed with approximately 53.86% to genetic divergence among genotypes.
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Cosentino, Bradley J., Christopher A. Phillips, Robert L. Schooley, Winsor H. Lowe, and Marlis R. Douglas. "Linking extinction–colonization dynamics to genetic structure in a salamander metapopulation." Proceedings of the Royal Society B: Biological Sciences 279, no. 1733 (November 23, 2011): 1575–82. http://dx.doi.org/10.1098/rspb.2011.1880.
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Theory predicts that founder effects have a primary role in determining metapopulation genetic structure. However, ecological factors that affect extinction–colonization dynamics may also create spatial variation in the strength of genetic drift and migration. We tested the hypothesis that ecological factors underlying extinction–colonization dynamics influenced the genetic structure of a tiger salamander ( Ambystoma tigrinum ) metapopulation. We used empirical data on metapopulation dynamics to make a priori predictions about the effects of population age and ecological factors on genetic diversity and divergence among 41 populations. Metapopulation dynamics of A. tigrinum depended on wetland area, connectivity and presence of predatory fish. We found that newly colonized populations were more genetically differentiated than established populations, suggesting that founder effects influenced genetic structure. However, ecological drivers of metapopulation dynamics were more important than age in predicting genetic structure. Consistent with demographic predictions from metapopulation theory, genetic diversity and divergence depended on wetland area and connectivity. Divergence was greatest in small, isolated wetlands where genetic diversity was low. Our results show that ecological factors underlying metapopulation dynamics can be key determinants of spatial genetic structure, and that habitat area and isolation may mediate the contributions of drift and migration to divergence and evolution in local populations.
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Alves, Rodrigo P., Ana Veruska C. Silva, Camila S. Almeida-Pereira, Tatiana S. Costa, Sheila V. Alvares-Carvalho, Maria de Fatima Arrigoni-Blank, and Arie F. Blank. "Genetic divergence in basil cultivars and hybrids." Horticultura Brasileira 37, no. 2 (June 2019): 180–87. http://dx.doi.org/10.1590/s0102-053620190208.
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ABSTRACT Basil is an aromatic herb that stands out for its economic importance. It is consumed in natura and used to obtain essential oil. The cultivation of this species in several regions of the world has allowed variations by natural crosses and euploidy, leading to the wide genetic variability found nowadays. Considering the importance of this species, we aimed to analyze the genetic diversity of 27 basil genotypes using ISSR molecular markers. Fourteen primers were employed for DNA amplification, resulting in 86% polymorphism. Based on the Jaccard’s dissimilarity index, the highest index (0.80) was observed between the individuals BAS001 and BAS012, while the lowest index (0.18) was detected between the genotypes BAS014 and BAS015. The genetic similarity among individuals was calculated, forming four distinct clusters. Most individuals (40.7%) were allocated in cluster I. The polymorphic information content (PIC) (0.89) indicated considerable levels of genetic diversity among genotypes. In this sense, the ISSR markers were efficient in the detection of polymorphisms between the accessions, suggesting the genetic variability of the collection. This result demonstrates the importance of the use of molecular markers and the advantages that this information provides to the breeding of the species.
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Bhajantri, Archana, and V. S. Patil. "Genetic diversity analysis in Gladiolus genotypes (Gladiolus hybridus Hort)." Journal of Applied and Natural Science 8, no. 3 (September 1, 2016): 1416–20. http://dx.doi.org/10.31018/jans.v8i3.975.
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In the present investigation, thirty gladiolus (Gladiolus hybridus Hort) genotypes were assessed to know the nature and magnitude of genetic divergence using Mahalanobis D2 statistics. Genetic diversity study indicated that among the 17 characters, most of the flower characters contributed towards diversity. Floret diameter contributed maximum towards genetic divergence followed by number of florets per spike, vase life, spike length and plant height.Thirty genotypes were grouped into 8 clusters and among them, cluster I was the largest with 9 genotypes followed by cluster II having 7 genotypes, and IV cluster 6 and cluster III with 3 genotypes each. Clusters were of V, VII and VIII solitary type means they having only one genotype in their group. Divergence values (D2 value) ranged from zero to 7.97 indicating considerable amount of moderate variability in the material studied. Information generated from the present study would be useful in selection of parents for future breeding programme for flower quality improvement in gladiolus. It is desirable to select genotypes from clusters having high cluster means and also with high flower character like spike length as parents for future recombination breeding programmes.
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Zebire, Degife Asefa. "Applications of molecular markers in Genetic Diversity Studies of maize." Nigerian Journal of Biotechnology 37, no. 1 (August 28, 2020): 101–8. http://dx.doi.org/10.4314/njb.v37i1.11.
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Molecular markers are efficient for exploiting variations in genotypes as they are not influenced by environmental factors and also speed up breeding programs. They are used to detect large numbers of distinct divergence between genotypes at the DNA level. Genetic diversity study helps to estimate the relationship between inbred lines to make the best hybrid combinations. Lines which are clustered in different heterotic groups are considered as the best hybrid combinations to carry out further breeding activities. Molecular markers are used to meet a number of objectives, including genetic diversity analysis and prediction of hybrid performances in divergent crop species. Agro-morphological and molecular markers have been utilized to study genetic diversity so far. In maize, the uses of molecular markers are important for the evaluation of genetic diversity of inbred lines and in clustering them into heterotic groups. These markers determine genetic similarity of the lines and are used to assess the genetic diversity of maize. Molecular markers have proven valuable for genetic diversity analysis of many crop species and genetically diverse lines are important to improve hybrid breeding.
Keyword: Molecular marker; Genetic diversity; Genetic variation, Diversity Array technology; cluster analysis
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Cunha, Andressa Maria, Mariana Terossi, Fernando Luis Mantelatto, and Alexandre Oliveira Almeida. "Genetic variation and cryptic diversity of the." Marine and Freshwater Research 73, no. 3 (November 22, 2021): 319–27. http://dx.doi.org/10.1071/mf21043.
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Alpheus lobidens sensu lato is one of the most common groups of snapping shrimps in the Indo-West Pacific. The objective of this study was to investigate the phylogenetic relationships among lineages of A. lobidens s.l. throughout their geographical distribution and identifying possible morphological characteristics that support the lineages from this combined dataset. Molecular data were obtained by analysing 16S rRNA from nine individuals of A. lobidens, three of A. buckupi, one of A. inopinatus and six other Alpheus species. The genetic analyses (mean p-distance and Bayesian Inference) indicate considerable genetic divergence and at least nine lineages within the A. lobidens species complex. The high morphological variability observed in Alpheus spp. and the high rates of interspecific genetic divergence agree with the Marine Ecoregions of the World and ocean currents, which suggests limited gene flow among those lineages, indicating that these could be treated as new species. However, as no informative morphological characters were identified, describing the six new taxa of the complex recognised in this study was unfeasible. Future studies using a higher number of specimens and applying more sensitive methods for detecting structural differences, might help morphologically define the new species that were uncovered herein.
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Islam, Md Mizan Ul, Parth Sarothi Saha, Tusher Chakrobarty, Nibir Kumar Saha, Md Sirajul Islam, and MA Salam. "Genetic diversity of aromatic rice in Bangladesh." Research in Agriculture Livestock and Fisheries 4, no. 1 (April 30, 2017): 1–6. http://dx.doi.org/10.3329/ralf.v4i1.32399.
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The nature and magnitude of diversity in 53 aromatic rice genotypes was evaluated in rain fed condition at BRAC Agricultural Research and Development Centre, Gazipur in 2012. The Euclidian method of divergence analysis indicated the presence of appreciable amount of genetic diversity in the material. These aromatic rice genotypes were grouped into six clusters where cluster I was the largest. Inter-cluster distances were larger than the intra-cluster distance revealed that there situated considerable genetic diversity among the genotypes. Based on positive value of vector I and II days to 50% flowering, seed length, and grain yield per hill had maximum contribution towards genetic divergence. Maximum yield contributing traits were accumulated in cluster V and as a result higher grain yield (42.0 g/hill) was obtained in this cluster. The genotypes of cluster V can be used in hybridization program to produce higher yielding breeding materials with all other clusters. The genotypes Cluster IV and cluster V were found most suitable for the respective characters and can be used as potential donor for future breeding programs.Res. Agric., Livest. Fish.4(1): 1-6, April 2017
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Mascarenhas Maciel, Gabriel, Fábio Janoni Carvalho, Camila Soares de Oliveira, Aline José da Silveira, Lucas Medeiros Pereira, and Igor Forigo Beloti. "GENETIC DIVERSITY OF BRAZILIAN PEPPER BASED ON QUALITATIVE REPRODUCTIVE TRAITS." Revista Ciência Agrícola 17, no. 3 (December 31, 2019): 1. http://dx.doi.org/10.28998/rca.v17i3.7758.
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In Brazil, pepper cultivation gives producers more marketing opportunities in various segments, either for fresh consumption or industry. Reproductive traits are efficient methods for comparing genetic divergence in pepper, once most differences among accessions could be verified at this stage. This study aimed to evaluate the genetic divergence in the reproductive phase of pepper accessions by multivariate analysis and test the efficiency of different methods. Sixty-five genotypes from the Federal University of UberlândiaCapsicum spp. Germplasm Bank were evaluated 145 days after sowing, and morphological characterization was performed at reproductive phase. Graphical representation of genetic distances was obtained by UPGMA. Tocher optimization method was also used to group accessions. Genotypes were arranged in seventeen different groups by Tocher method. UPGMA dendrogram collaborated with Tocher method, indicating the wide genetic variability of genotypes. Tocher and UPGMA methods were partially in agreement, allowing grouping 44 of the 65 analyzed accessionsequally. Multicategorical traits have the advantage of easy observation and require less time and labor, being ideal for use in gene bank and collections that do not have high human and financial resources. Moreover, these traits are not affected by the environment. Genetic divergence detected in this paper encourages other researchers to perform the characterization of pepper collections as completely as possible, because it becomes possible to generate more reliable information of the variability and genetic divergence among accessions. Our research discloses the reproductive biodiversity of pepper in “Alto Paranaíba” and “TriânguloMineiro” regions and the importance of maintaining these genotypes.
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Gorel, Anaïs-Pasiphaé, Jérôme Duminil, Jean-Louis Doucet, and Adeline Fayolle. "Ecological niche divergence associated with species and populations differentiation in Erythrophleum (Fabaceae, Caesalpinioideae)." Plant Ecology and Evolution 152, no. 1 (March 25, 2019): 41–52. http://dx.doi.org/10.5091/plecevo.2019.1543.
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Background and aims – The isolation of populations inside forest refugia during past climate changes has widely been hypothesized as a major driver of tropical plant diversity. Environmental conditions can also influence patterns of diversity by driving divergent selection leading to local adaptation and, potentially, ecological speciation. Genetic and phylogenetic approaches are frequently used to study the diversification of African tree clades. However, the environmental space occupied by closely related species or intra-specific gene pools is barely quantified, though needed to properly test hypotheses on diversification processes.Methods – Using species distribution models, we determined the bioclimatic constraints on the distribution of closely related species and intra-specific gene pools. Our study model, Erythrophleum (Fabaceae – Caesalpinioideae), is a tropical tree genus widespread across Africa, and vastly investigated for genetics. Here, we combined the available phylogenetic data with information on niche divergence to explore the role of ecology into diversification at the species and gene pool levels.Key results – Ecological speciation through climate has probably played a key role in the evolution of the Erythrophleum species. The differential climatic niche of the species indicated adaptive divergence along rainfall gradients, that have probably been boosted by past climate fluctuations. At the gene pool level, past climate changes during the Pleistocene have shaped genetic diversity, though within Erythrophleum suaveolens, adaptive divergence also occurred.Conclusions – We believe that ecological speciation is a key mechanism of diversification for tropical African tree species, since such climatic niche partition exist among many other genera. Modelling the environmental niche of closely related taxa, and testing for niche differentiation, combined with divergence dates offered new insights on the process of diversification.
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Aradhva, K. M., F. Zee, and R. M. Manshardt. "Genetic Diversity in Nephelium." HortScience 30, no. 4 (July 1995): 795F—795. http://dx.doi.org/10.21273/hortsci.30.4.795f.
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Fifty-six accessions involving five taxa of Nephelium (N. Iappaceum varieties lappaceum and pallens, N. hypoleucum, N. ramboutan-ake, and N. cuspidatum) were fingerprinted and evaluated for genetic diversity using isozyme polymorphism. All five taxa were polymorphic for most of the enzymes encoded by 10 putative loci. Number of alleles per locus ranged from three for Pgi-1 to nine for Pgi-2 with a total of 57 alleles. Thirty-eight accessions out of 56 possessed unique isozyme genotypes, indicating a high level of diversity in the collection. On average, 80% of the loci were polymorphic and the expected and observed heterozygosities were 0.374 and 0.373, respectively. The cluster analysis of the isozyme data revealed five distinct clusters representing the five taxa included in the study. Genetic differentiation within N. Iappaceum var. Iappaceum was evident from the cluster analysis. Isozyme data indicated that N. ramboutan-ake is the closest relative of N. Iappaceum var. Iappaceum, followed by N. hypoleucum, N. Iappaceum var. pallens, and N. cuspidatum. Interestingly, the varieties of N. Iappaceum exhibited genetic divergence far beyond that of the congenerics, N. hypoleucum and N. ramboutan-ake and may require a taxonomic revision.
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Draškić, Gordon, Sansareeya Wangkulangkul, Iñigo Martínez-Solano, and Judit Vörös. "Strong genetic subdivision in Leptobrachium hendricksoni (Anura: Megophryidae) in Southeast Asia." Amphibia-Reptilia 39, no. 1 (2018): 99–111. http://dx.doi.org/10.1163/15685381-17000102.
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Many biodiversity hotspots are located in areas with a complex geological history, like Southeast Asia, where species diversity may still be far underestimated, especially in morphologically conservative groups like amphibians. Recent phylogenetic studies on the frog genusLeptobrachiumfrom Southeast Asia revealed the presence of deeply divergent mitochondrial clades inLeptobrachium hendricksonifrom Malaysia and Sumatra but populations from Thailand have not been studied so far. In this study, we re-evaluate patterns of intraspecific genetic diversity inL. hendricksonibased on the analysis of combined sequences of mitochondrial 12S and 16S genes (1310 base pairs) including for the first time samples from southern Thailand. Thai populations ofL. hendricksoniformed a distinct clade with respect to populations from central and southern Malaysia and Sumatra. High sequence divergence between lineages from Thailand, Malaysia and Sumatra suggests the possible presence of cryptic species inL. hendricksoni. Divergence withinL. hendricksonidates back to the late Miocene, around 6 Mya, when lineages from Thailand, north Malaysia and Sumatra split from a lineage in south Malaysia, at about the same time as rising sea levels isolated the Thai-Malay peninsula. Subsequent splits took place later in the Pliocene, around 4.5 and 2.6 Mya. Our results highlight the role of geological history in promoting population divergence and speciation.
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Oneal, Elen, and L. Lacey Knowles. "Ecological selection as the cause and sexual differentiation as the consequence of species divergence?" Proceedings of the Royal Society B: Biological Sciences 280, no. 1750 (January 7, 2013): 20122236. http://dx.doi.org/10.1098/rspb.2012.2236.
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Key conceptual issues about speciation go unanswered without consideration of non-mutually exclusive factors. With tests based on speciation theory, we exploit the island distribution and habitat differences exhibited by the Caribbean cricket Amphiacusta sanctaecrucis , and with an analysis of divergent ecological selection, sexually selected differentiation and geographical isolation, address how these different factors interact. After testing for divergent selection by comparing neutral genetic and morphological divergence in one ecological (mandible shape) and one sexual (male genitalia shape) trait, we examine whether ecological or sexual selection is the primary mechanism driving population divergence. We find that all three factors—isolation, ecological and sexual selection—contribute to divergence, and that their interaction determines the stage of completeness achieved during the speciation process, as measured by patterns of genetic differentiation. Moreover, despite the striking diversity in genitalic shapes across the genus Amphiacusta , which suggests that sexual selection drives speciation, the significant differences in genitalia shape between forest habitats revealed here implies that ecological divergence may be the primary axis of divergence. Our work highlights critical unstudied aspects in speciation—differentiating the cause from the consequence of divergence—and suggests avenues for further disentangling the roles of natural and sexual selection in driving divergence in Amphiacusta .
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Alam, Md Sarowar, Md Samsuzzaman, Md Abdul Mazed Miah, Mirana Akter Sumi, and Md Ahasan Habib. "EVALUATION AND GENETIC DIVERSITY ANALYSIS OF LOCAL MANGO GERMPLASM." Acta Scientifica Malaysia 6, no. 1 (2022): 23–27. http://dx.doi.org/10.26480/asm.01.2022.23.27.
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The experiment was conducted during 2019-2021 at Regional Agricultural Research Station, Akbarpur, Moulvibazar, Bangladesh with twenty-three local mango genotypes to assess the performance and genetic divergence for the identification of suitable parents for the futute breeding program. . Wide variations were observed regarding the number of fruits/plant, fruit weight, percent of edible portion, and TSS of different germplasms. The highest number of fruit per plant (610) was observed in MIAkb001, highest individual fruit weight /plant (759.7g) was obtained from MIAkb015. The higher fruit yield was recorded from MIAkb001 (162.07kg). The percent of the edible portion was higher in MIAkb014 (65.71%) whereas maximum TSS (18%) was obtained from MIAkb007 andMIAkb015 respectively. The genetic divergence was assessed in 23 mango genotypes through multivariate analysis. The genotypes under this study were grouped into five clusters and the diversity was influenced by the morphological characters. The highest number (8) of genotypes were in cluster-I and the lowest (1) number of the genotype was in cluster-III. From the PCA we found, the number of fruits per plant (FNPP), fruits yield per plant (FYPP), and individual fruit weight were positive across the two axes, and these were the main traits for genetic divergence.
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Matias, Rosana Gonçalves Pires, Cláudio Horst Bruckner, João Alison Alves Oliveira, Pedro Crescêncio Souza Carneiro, Danielle Fabíola Pereira Silva, and Carlos Eduardo Magalhães Santos. "Genetic diversity in peach cultivars." Comunicata Scientiae 7, no. 3 (December 27, 2016): 293. http://dx.doi.org/10.14295/cs.v7i3.1254.
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This study aimed to evaluate the genetic diversity among 28 peach cultivars and two nectarine cultivars, describing the most important characters in the diversity evaluation. The study was developed at the Federal University of Viçosa - Brazil, and the following characteristics were evaluated: fruit mass, suture, equatorial and polar diameters, firmness, soluble solids (SS), titratable acidity (TA), SS/TA, ascorbic acid and carotenoids contents, skin and flesh color (coordinate b* and hue angle - °h). Genetic diversity in peach and nectarine cultivars enabled the formation of seven, six and six groups in the 2011, 2012 and 2013 crop years, respectively. The features that most contributed to this diversity were fruit mass, skin and flesh °h and firmness. The greatest genetic divergence was observed between ‘Marli’ and ‘Rubrosol’, ‘Josefina’ and ‘Maciel’ and ‘Maciel’ and ‘Rubrosol’ during the 2011, 2012 and 2013 crop years, respectively.
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Oliveira, Rebeca Lourenço de, Leandro Simões Azeredo Gonçalves, Rosana Rodrigues, Viviane Yumi Baba, Cláudia Pombo Sudré, Marilene Hilma dos Santos, and Fabrizio Malaghini Aranha. "Genetic divergence among pumpkin landraces." Semina: Ciências Agrárias 37, no. 2 (April 26, 2016): 547. http://dx.doi.org/10.5433/1679-0359.2016v37n2p547.
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Estimating the genetic variability in germplasm collections is important not only for conserving genetic resources, but also for plant breeding purposes. However, generating a large number of different categories data (qualitative and quantitative) often complicate the analysis and results interpretation, resulting in an incomplete distinction of accessions. This study reports the characterization and evaluation of 14 pumpkin (Cucurbita moschata) accessions collected from farms in the northern region of Rio de Janeiro state. Genetic diversity among accessions was also estimated using qualitative and quantitative variables considering joint analysis. The plants were grown under field conditions in a randomized block design with three replications and six plants per plot. Eight qualitative traits (leaf size; seed shape; seed color; color of the fruit pulp; hollow; fruit shape; skin color, and fruit skin texture) and eight quantitative traits (fruit weight; fruit length; fruit diameter; soluble solids, 100 seed weight, and wall thickness measured in the middle and in the lower stem) were evaluated. The data were analyzed considering the Gower distance, and cluster analysis was performed using unweighted pair group method with arithmetic mean (UPGMA). Variability among accessions was observed considering morphoagronomic data. The Gower distance together with UPGMA cluster allowed for good discrimination between accessions in the groups, demonstrating that the simultaneous analysis of qualitative and quantitative data is feasible and may increase the understanding of the variation among accessions.
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Takahata, Naoyuki. "Gene diversity in finite populations." Genetical Research 46, no. 1 (August 1985): 107–13. http://dx.doi.org/10.1017/s0016672300022503.
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DNA sequence comparison among homologous genes sampled at random from one or two populations allows one to estimate the ultimate amount of genetic variation maintained in a population and to construct the gene genealogy within and between populations. Moreover, if we use the finding of the molecular clock (Zuckerkandl & Pauling, 1965), it is also possible to estimate the divergence time of populations examined. Such an estimated divergence time is, however, intricately affected by samples and stochastic forces occurring in the course of evolution.
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Bruel, Daniela Cristina, Valéria Carpentieri-Pípolo, Antonio Carlos Gerage, Nelson da Silva Fonseca Júnior, Cássio Egídio Cavenaghi Prete, Claudete de Fátima Ruas, Paulo Maurício Ruas, Silvia Graciele Hülse de Souza, and Deoclécio Domingos Garbuglio. "Genetic distance estimated by RAPD markers and its relationship with hybrid performance in maize." Pesquisa Agropecuária Brasileira 41, no. 10 (October 2006): 1491–98. http://dx.doi.org/10.1590/s0100-204x2006001000006.
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The objective of this work was to evaluate the genetic diversity of 16 maize inbred lines, and to determine the correlation between genetic distance and hybrid performance, using random amplified polymorphic DNA (RAPD) molecular markers. Twenty-two different random primers were used, which resulted in the amplification of 265 fragments, 237 (84.44%) of them being polymorphic. A genetic similarity matrix was created from the RAPD data, using Jaccard coefficient, and a dendrogram was constructed. Hybrid analyses were carried out using random block design and Griffing method VI for diallel crossings. The genetic associations showed five distinct heterotic groups. Correlations between genetic divergences detected by RAPD, as well as the means observed in the diallel crossings were positive and significant for plant height, ear height, prolificacy, and grain weight. The correlation of genetic divergences, detected by RAPD, and the specific combining ability between heterotic group associations, showed significance in all characteristics under study, except prolificacy. A direct relationship between genetic divergence and productivity was found in 79.2% of the 120 hybrids confirming the hypothesis that genetic divergence is directly related to the performance of hybrids and is efficient in predicting it.
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Buhroo, Zafar Iqbal, and Muzafar Ahmad Bhat*. "Molecular marker systems with special reference to the Silkworm Bombyx mori L." International Journal of Bioassays 5, no. 11 (October 31, 2016): 5025. http://dx.doi.org/10.21746/ijbio.2016.11.007.
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Study on genetic diversity is critical to success in any crop breeding and it provides information about the quantum of genetic divergence and serves a platform for specific breeding objectives. Genetic diversity is a particular concern because greater genetic uniformity in silkworm can increase vulnerability to pests and diseases. Hence maintenance of genetic diversity is a fundamental component in long term management strategies for genetic improvement of silkworm which is cultivated by millions of people around the worlds for its lustrous silk. In view of the present study, genetic diversity studies carried out in silkworm using divergent methods (Quantitative traits, biochemical and molecular markers) and present level of diversity, pertaining to the literature has been reviewed. Genetic diversity is the genetic variation within species, both among geographically separated populations and among individuals within a single population. Genetic diversity is an essential aspect in conservation biology because a fundamental concept of natural selection states that the rate of evolutionary change in a population is proportional to the amount of genetic diversity present in it. Decreasing genetic diversity increases the extinction risk of populations due to a decline in fitness. Therefore, both biochemical and molecular markers have recently been employed to estimate the extent of genetic diversity present among various types of silkworm strains such as mono-, bi and multivoltines present in China, Japan, Korea, India, and several other countries.
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Ladner, Jason T., Nazir Savji, Loreen Lofts, Amelia Travassos da Rosa, Michael R. Wiley, Marie C. Gestole, Gail E. Rosen, et al. "Genomic and phylogenetic characterization of viruses included in the Manzanilla and Oropouche species complexes of the genus Orthobunyavirus, family Bunyaviridae." Journal of General Virology 95, no. 5 (May 1, 2014): 1055–66. http://dx.doi.org/10.1099/vir.0.061309-0.
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A thorough characterization of the genetic diversity of viruses present in vector and vertebrate host populations is essential for the early detection of and response to emerging pathogenic viruses, yet genetic characterization of many important viral groups remains incomplete. The Simbu serogroup of the genus Orthobunyavirus, family Bunyaviridae, is an example. The Simbu serogroup currently consists of a highly diverse group of related arboviruses that infect both humans and economically important livestock species. Here, we report complete genome sequences for 11 viruses within this group, with a focus on the large and poorly characterized Manzanilla and Oropouche species complexes. Phylogenetic and pairwise divergence analyses indicated the presence of high levels of genetic diversity within these two species complexes, on a par with that seen among the five other species complexes in the Simbu serogroup. Based on previously reported divergence thresholds between species, the data suggested that these two complexes should actually be divided into at least five species. Together these five species formed a distinct phylogenetic clade apart from the rest of the Simbu serogroup. Pairwise sequence divergences among viruses of this clade and viruses in other Simbu serogroup species complexes were similar to levels of divergence among the other orthobunyavirus serogroups. The genetic data also suggested relatively high levels of natural reassortment, with three potential reassortment events present, including two well-supported events involving viruses known to infect humans.
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Amin, MF, M. Hasan, NCD Barma, MG Rasul, and MM Rahman. "Genetic diversity analysis in spring wheat (Triricum aestivum L.)." Bangladesh Journal of Agricultural Research 39, no. 2 (September 11, 2014): 189–96. http://dx.doi.org/10.3329/bjar.v39i2.20414.
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Genetic divergences of 50 wheat lines were studied through Mohalanobiss D2 and principal component analysis for fourteen characters. Genotypes were grouped into four different clusters. Cluster II comprised maximum number of genotypes (twenty one) followed by cluster IV. The inter-cluster distance was maximum between clusters I and III (12.29) indicating wide genetic diversity between these two clusters followed by the distance between cluster I and cluster II (8.28), and cluster III and cluster IV (7.97). The minimum inter-cluster distance was observed between cluster II and cluster IV (4.193) followed by cluster I and cluster IV (4.339) and cluster II and cluster III(4.390) indicating that the genotypes of these clusters were genetically close. The intra cluster distance of all the four clusters was more or less low which indicated that the genotypes within the same cluster were closely related. The highest inter genotypic distance (0.9166) was observed between the genotypes G 40 and G 41and lowest (0.0993) between the genotypes G 22 and G 43. Among the characters, heading days, maturity days, plant height (cm), canopy temperature at vegetative stage, canopy temperature at grain filling stage, grain filling rate (g d-1m-2), 1000- grain weight (g), and grains spike-1 contributed most for divergence in the studied genotypes. Cluster I had the highest mean for grain yield (4711.2 kg/ha), grain filling rate (17.5 g d-1m-2), chlorophyll content at anthesis, and plant height (93 cm). Crosses between I & III, I & II, and III & IV have greater chances to generate more heterotic F1s. Considering magnitude of genetic distance, contribution of different traits toward the total divergence, magnitude of cluster means for different traits and performance the genotypes G10, G 11, G12, G35, G40, G48 of cluster I, G7 of cluster II, G41, G5,and G3 of cluster III and G46, G21 of cluster IV may be considered as good parents for future hybridization program to produce high yielding genotypes. DOI: http://dx.doi.org/10.3329/bjar.v39i2.20414 Bangladesh J. Agril. Res. 39(2): 189-196, June 2014
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Genty, Gabrielle, Carlos E. Guarnizo, Juan P. Ramírez, Lucas S. Barrientos, and Andrew J. Crawford. "Landscape Genetics and Species Delimitation in the Andean Palm Rocket Frog (Aromobatidae, Rheobates)." Journal of Zoological Systematics and Evolutionary Research 2022 (February 9, 2022): 1–12. http://dx.doi.org/10.1155/2022/6774225.
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The complex topography of the species-rich northern Andes creates heterogeneous environmental landscapes that are hypothesized to have promoted population fragmentation and diversification by processes such as vicariance or local adaptation. Previous phylogenetic work on the palm rocket frog (Anura: Aromobatidae: Rheobates spp.), endemic to midelevation forests of Colombia, suggested that valleys were important in promoting divergence between lineages. In this study, we first evaluated previous hypotheses of species-level diversity, then fitted an isolation-with-migration (IM) historical demographic model, and tested two landscape genetic models to explain genetic divergence within Rheobates: isolation by distance and isolation by environment. The data consisted of two mitochondrial and four nuclear genes from 24 samples covering most of the geographic range of the genus. Species delimitation by Bayesian Phylogenetics and Phylogeography recovered five highly divergent genetic lineages within Rheobates, among which few to no migrants are exchanged according to IM. We found that isolation by environment provided the only variable significantly correlated with genetic distances for both mitochondrial and nuclear genes, suggesting that local adaptation may have a role in driving the genetic divergence within this frog genus. Thus, genetic divergence in Rheobates may be driven more by variation among the local environments where these frogs live rather than by geographic distance.
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Singh, RK, BK Dubey, and RP Gupta. "Intra and Inter Cluster Studies for Quantitative Traits in Garlic (Allium sativum L)." SAARC Journal of Agriculture 11, no. 2 (March 20, 2014): 61–67. http://dx.doi.org/10.3329/sja.v11i2.18402.
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Garlic is propagated vegetatively, the clonal selection is the important breeding method and very scanty work has been done on the association between different traits in garlic. Analysis of variance revealed significant divergence in fifteen garlic clone with checks i. e. Yamuna Safed (G-1), Agrifound White (G-41), Yamuna Safed-2 (G-50) and Yamuna Safed-3 (G-282) for different traits, indicating sufficient genetic diversity among the cultivars. Genotypes belonging to the cluster with maximum inter cluster distance were genetically more divergent. Therefore, it is suggested that based upon large cluster distances to select genotypes from all the clusters, which may lead to broad spectrum of favorable genetic variability for bulb yield improvement. Cluster-III had highest value of plant height (93.05 cm), bulb diameter (4.71 cm), bulb size index (16.08 cm2), 20 bulb weight (700 g), clove diameter (1.75 cm), clove size index (4.43 cm2), weight of 50 cloves (97.50 g) and gross yield (159.63 t ha-1) and minimum neck thickness (1.45 cm) number of cloves per bulbs (17) days for bulb initiation (61.66 days) and days to harvesting (149.83). The traits total soluble solids contributed maximum (20.46%) toward genetic divergence followed by gross yield (16.37%), bolters (12.86%), marketable yield (11.11%), number of cloves per bulbs (10.52%), weight of 50 cloves (10.52%), days for bulb initiation (10.52%) and days for harvesting (4.09%). These traits were considered to be most important for genetic divergence, they contributed (96.45%) towards genetic divergence and selection of genotypes based on these traits will contribute to wider genetic diversity in the existing gene pool of garlic genotypes. DOI: http://dx.doi.org/10.3329/sja.v11i2.18402 SAARC J. Agri., 11(2): 61-67 (2013)
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Billington, Neil, and Paul D. N. Hebert. "Mitochondrial DNA Diversity in Fishes and its Implications for Introductions." Canadian Journal of Fisheries and Aquatic Sciences 48, S1 (December 19, 1991): 80–94. http://dx.doi.org/10.1139/f91-306.
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Patterns of mitochondrial DNA (mtDNA) variation have now been examined in more than 40 fish species. This work has established that mitochondrial genomes of fish show constrained size variation, but that genomes of closely related species often vary in size, suggesting that counterbalancing deletions and insertions act to stabilize genome size. Gene order and composition are also stable, but nucleotide sequences show rapid divergence. Populations of most fish species contain a few common mtDNA haplotypes and a spectrum of their rare mutational derivatives. The extent of genetic divergence among dominant haplotypes seems linked to environmental conditions with greater divergence in freshwater than marine species, especially those occupying unglaciated localities. Haplotype frequencies ordinarily show considerable local divergence, largely as a result of stochastic shifts associated with population founding events. Such divergence provides a basis for both the discrimination of local stocks and for the recognition of major genetic discontinuities reflecting past episodes of gene pool fragmentation. Analysis of hatchery stocks has often revealed their mtDNA divergence, but in most cases stocks are fixed for haplotypes which are also common in wild populations. There is, however, the opportunity to develop brood-stocks marked with rare haplotypes, permitting their recognition in nature over many generations.
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ULUAR, ONUR, ÖZGÜL YAHYAOĞLU, and BATTAL ÇIPLAK. "Anatolian endemic genus Bolua (Orthoptera: Tettigoniidae: Tettigoniinae): genetic and phenotypic data indicate inconsistent diversity and evolutionary patterns." Zootaxa 5195, no. 3 (October 12, 2022): 224–40. http://dx.doi.org/10.11646/zootaxa.5195.3.2.
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Anatolia harbours diverse and unique biodiversity. Nearly half of the genera and more than 80% of the species belonging to the tettigoniid subfamily Tettigoniinae are endemic to Anatolia. Although the Anatolian Tettigoniinae have been well studied, proper documentation of Tettigoniinae biodiversity requires studies using contemporary approaches and techniques. We attempted to study the taxonomy, phylogeny, and phylogeography of the Bolua, a monotypic genus endemic to northwest Anatolia. Species delimitation tests applied to three mitochondrial and two nuclear gene segments indicated three putative species in the genus. Analyses suggested inversely related genetic and phenotypic divergence. By integrating these results, we reached the following conclusions. (i) The plausible taxonomic composition recognizes three species in the genus; the type species Bolua turkiyae and two new species B. balikesirensis sp. n. and B. bursaensis sp. n., (ii) the radiation steps in Bolua correspond to the starting of the Pliocene, Mid Pleistocene Transition (MPT) and end of cold periods of Günz and Riss glacial. By considering intra generic divergence steps and habitat preference plus the distribution pattern of the species, ecological speciation seems to be the mode of generic radiation, (iii) possibly due to habitat conservatism, the isolated relict populations on highlands evolved under similar selection pressures, and this led to a conserved phenotype, consequently morphologically poorly diverged species, though genetic divergence is deep and (iv) although morphological diagnoses is poor, genetic divergence between species is deep, and each species fulfils the criteria of several species concepts.
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Ayyappan Korattukudy, Chippy, Andrew Peter Leon Michael Antony Samy Tamilarasi, Kannan Rengasamy, Shoba Devadhasan, Saravanan Shunmugavel, Jeshima Khan Yasin, and Arumugam Pillai Madhavan. "Genetic diversity analysis in blackgram (Vigna mungo) genotypes using microsatellite markers for resistance to Yellow mosaic virus." Plant Protection Science 58, No. 2 (March 28, 2022): 110–24. http://dx.doi.org/10.17221/8/2020-pps.
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One hundred and two blackgram genotypes were evaluated for Yellow mosaic virus (YMV) resistance based on disease scoring, molecular characterisation, yield and morphological observation. An analysis of variance and a correlation analysis were performed on nine biometric traits. The genotypes showed the highest genetic variation for a single plant yield (genotypic coefficient variation 42.72%). The genotypes were grouped into 18 clusters based on the morphological data. The genetic divergence among the blackgram genotypes was differentiated by 60 alleles using 14 polymorphic simple sequence repeat markers. The polymorphism information content value varied from 0.37 to 0.79. The multivariate analyses of the simple sequence repeat marker scorings divided the germplasm into five divergent clusters wherein, clusters viz., II, III and V accommodated 61 genotypes and all these genotypes were resistant to moderately resistant for YMV. The tolerant accessions identified from this present investigation can be directly used for further crop improvement programmes.
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Henk, Daniel A., and Matthew C. Fisher. "Genetic Diversity, Recombination, and Divergence in Animal Associated Penicillium dipodomyis." PLoS ONE 6, no. 8 (August 5, 2011): e22883. http://dx.doi.org/10.1371/journal.pone.0022883.
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Gyllensten, U., M. Sundvall, I. Ezcurra, and H. A. Erlich. "Genetic diversity at class II DRB loci of the primate MHC." Journal of Immunology 146, no. 12 (June 15, 1991): 4368–76. http://dx.doi.org/10.4049/jimmunol.146.12.4368.
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Abstract The evolution of polymorphism at loci encoding the beta-chains of the MHC class II DR Ag was studied in primates by DNA amplification (polymerase chain reaction). Phylogenetic analysis of 63 DRB sequences from the polymorphic second exon (first domain) of nonhuman primates and 53 human sequences indicates the presence of five DRB loci in primates, derived from a DRB1-like ancestral locus over 20 million yr ago. Many of the allelic types at the DRB1 locus predate the divergence of hominoids (5 million yr ago) and some (DR4, DR3, 5, 6) predate the divergence of Old world monkeys and hominoids (20 million yr ago). The DRB3 locus appears to have arisen before the divergence of hominoids on an ancestral DRB1 lineage. The DRB2 and DRB5 loci were generated more than 20 million yr ago and the DRB4 locus more than 5 million yr ago. The DRB2 locus, a pseudogene in humans, is polymorphic in the nonhuman primates.
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VANDERGAST, AMY G., WILLIAM M. PERRY, ROBERTO V. LUGO, and STACIE A. HATHAWAY. "Genetic landscapes GIS Toolbox: tools to map patterns of genetic divergence and diversity." Molecular Ecology Resources 11, no. 1 (August 16, 2010): 158–61. http://dx.doi.org/10.1111/j.1755-0998.2010.02904.x.
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Wang, Da, Xiaoqin Shi, Deguang Liu, Yujing Yang, and Zheming Shang. "Genetic Divergence of Two Sitobion avenae Biotypes on Barley and Wheat in China." Insects 11, no. 2 (February 11, 2020): 117. http://dx.doi.org/10.3390/insects11020117.
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Host plant affinity and geographic distance can play critical roles in the genetic divergence of insect herbivores and evolution of insect biotypes, but their relative importance in the divergence of insect populations is still poorly understood. We used microsatellite markers to test the effects of host plant species and geographic distance on divergence of two biotypes of the English grain aphid, Sitobion avenae (Fabricius). We found that clones of S. avenae from western provinces (i.e., Xinjiang, Gansu, Qinghai and Shaanxi) had significantly higher genetic diversity than those from eastern provinces (i.e., Anhui, Henan, Hubei, Zhejiang and Jiangsu), suggesting their differentiation between both areas. Based on genetic diversity and distance estimates, biotype 1 clones of eastern provinces showed high genetic divergence from those of western provinces in many cases. Western clones of S. avenae also showed higher genetic divergence among themselves than eastern clones. The Mantel test identified a significant isolation-by-distance (IBD) effect among different geographic populations of S. avenae, providing additional evidence for a critical role of geography in the genetic structure of both S. avenae biotypes. Genetic differentiation (i.e., FST) between the two biotypes was low in all provinces except Shaanxi. Surprisingly, in our analyses of molecular variance, non-significant genetic differentiation between both biotypes or between barley and wheat clones of S. avenae was identified, showing little contribution of host-plant associated differentiation to the divergence of both biotypes in this aphid. Thus, it is highly likely that the divergence of the two S. avenae biotypes involved more geographic isolation and selection of some form than host plant affinity. Our study can provide insights into understanding of genetic structure of insect populations and the divergence of insect biotypes.
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Nikolic, Ana, Natalija Kravic, Jelena Srdic, Dragan Kovacevic, Violeta Andjelkovic, Milomir Filipovic, and Snezana Mladenovic-Drinic. "Divergence among maize genotypes with different kernel types according to SSR marker analysis." Genetika 51, no. 1 (2019): 237–49. http://dx.doi.org/10.2298/gensr1901237n.
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Panels of diverse materials have proven to be very useful in evaluation of the organization of genetic diversity available for breeding at phenotypic and genotypic levels. In this study, a panel consisting of several groups of maize inbreds was tested using microstelite markers. The aim of this study was to test genetic diversity and define population structure of twenty-four genotypes differing in kernel type (dent, flint, popcorn, sweet maize) and kernel color (white, yellow, orange) with 21 SSRs. Genetic diversity parameters such as number of alleles, gene diversity, observed heterozygosity, PIC (Polymorphism Information Content) and number of unique alleles were determined. In addition, genetic distances according to Rogers distance were calculated. The values for all parameters were high, reflecting high genetic divergence of analyzed germplasm. Distance matrix based on UPGMA cluster analysis showed moderate congruence to available pedigree/origin or kernel type/color data. Genetic structure of tested genotypes was defined using Bayesian model-based clustering, without a considerable difference in comparison to cluster data analysis. The determined diversity parameters along with the results concerning genetic structure analysis provided a valuable information for improved selection efficiency.