Genetic Structure and Population Demographic History of a Widespread Mangrove Plant Xylocarpus granatum J. Koenig across the Indo-West Pacific Region

The black fly Simulium aureohirtum Brunetti (Diptera: Simuliidae) is geographically widespread and utilizes diverse habitats. Previous studies revealed high genetic diversity, suggesting that this species could be a species complex. In this study, we used mitochondrial cytochrome c oxidase II sequences to examine genetic structure and demographic history of S. aureohirtum in Thailand. High level of genetic variation was observed due to the existence of genetically divergent lineages (A, B, and C). Lineages A and C were geographically widespread, while lineage B was geographically restricted to the eastern part of Thailand. The geographic localization of lineage B suggested limitations in gene flow, which is most likely a result of ecologically different habitats. Large genetic differences between individuals of lineages A and C, but geographically sympatric distributions of the members of these lineages, are considered to represent an admixture of the populations that have evolved allopatrically. Historical environmental change during the Pleistocene glaciations is possibly the factor that drove the lineage divergence. Population demographic history analyses revealed recent population expansions in the three lineages dating back to the last glaciations. These observations further highlight the significance of the Pleistocene climatic change on current genetic structure and diversity of living organisms of the Southeast Asian mainland.

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Population genetic structure and demographic history of Pacific blue sharks (Prionace glauca) inferred from mitochondrial DNA analysis

Marine and Freshwater Research ◽

10.1071/mf14075 ◽

2015 ◽

Vol 66 (3) ◽

pp. 267 ◽

Cited By ~ 17

Author(s):

Mioko Taguchi ◽

Jacquelynne R. King ◽

Michael Wetklo ◽

Ruth E. Withler ◽

Kotaro Yokawa

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Demographic History ◽

Pacific Region ◽

Genetic Structuring ◽

Blue Shark ◽

Prionace Glauca ◽

Mitochondrial Cytochrome B ◽

History Of

Cosmopolitan pelagic species often show shallow genetic divergence and weak, or no, genetic structure across a species’ range. However, there have been few such genetic studies for pelagic sharks. The pelagic blue shark (Prionace glauca) has a broad circumglobal distribution in tropical and temperate oceans. To investigate the population genetic structure and demographic history of this species, we analysed variation in the mitochondrial cytochrome b sequence for a total of 404 specimens collected from 10 locations across the Indo-Pacific region. The observed genetic diversities were comparable among sampling locations (h=0.77–0.87; π=0.17–0.23%). Spatial analysis of molecular variance (SAMOVA), pairwise ΦST and conventional FST estimates, and analysis of isolation with migration indicated weak or no genetic differentiation of this species across the Indo-Pacific region. The results of three phylogeographic analyses (i.e. mismatch distribution and parsimony haplotype network analyses and a neutrality test) suggested that the Pacific blue shark had historically experienced a sudden population expansion. These results, coupled with the biological properties of this species, imply that historical climate fluctuation has had only a minor effect on the genetic structuring of the blue shark.

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Genetic variability and demographic history of Heliothis virescens (Lepidoptera: Noctuidae) populations from Brazil inferred by mtDNA sequences

Bulletin of Entomological Research ◽

10.1017/s0007485311000678 ◽

2011 ◽

Vol 102 (3) ◽

pp. 333-343 ◽

Cited By ~ 16

Author(s):

K.C. Albernaz ◽

K.L. Silva-Brandão ◽

P. Fresia ◽

F.L. Cônsoli ◽

C. Omoto

Keyword(s):

Genetic Structure ◽

Genetic Variability ◽

Heliothis Virescens ◽

Demographic History ◽

Haplotype Diversity ◽

Low Frequency ◽

Haplotype Network ◽

Demographic Expansion ◽

Significant Genetic Structure ◽

History Of

AbstractIntra- and inter-population genetic variability and the demographic history of Heliothis virescens (F.) populations were evaluated by using mtDNA markers (coxI, coxII and nad6) with samples from the major cotton- and soybean-producing regions in Brazil in the growing seasons 2007/08, 2008/09 and 2009/10. AMOVA indicated low and non-significant genetic structure, regardless of geographical scale, growing season or crop, with most of genetic variation occurring within populations. Clustering analyzes also indicated low genetic differentiation. The haplotype network obtained with combined datasets resulted in 35 haplotypes, with 28 exclusive occurrences, four of them sampled only from soybean fields. The minimum spanning network showed star-shaped structures typical of populations that underwent a recent demographic expansion. The recent expansion was supported by other demographic analyzes, such as the Bayesian skyline plot, the unimodal distribution of paired differences among mitochondrial sequences, and negative and significant values of neutrality tests for the Tajima's D and Fu's FS parameters. In addition, high values of haplotype diversity (Ĥ) and low values of nucleotide diversity (π), combined with a high number of low frequency haplotypes and values of θπ<θW, suggested a recent demographic expansion of H. virescens populations in Brazil. This demographic event could be responsible for the low genetic structure currently found; however, haplotypes present uniquely at the same geographic regions and from one specific host plant suggest an initial differentiation among H. virescens populations within Brazil.

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The Genetic History of France

10.1101/712497 ◽

2019 ◽

Author(s):

Aude Saint Pierre ◽

Joanna Giemza ◽

Matilde Karakachoff ◽

Isabel Alves ◽

Philippe Amouyel ◽

...

Keyword(s):

Genetic Structure ◽

Demographic History ◽

Migration Routes ◽

Effective Population ◽

Genetic Studies ◽

Independent Population ◽

Genome Wide Data ◽

Population Sizes ◽

History Of ◽

Exhaustive Study

ABSTRACTThe study of the genetic structure of different countries within Europe has provided significant insights into their demographic history and their actual stratification. Although France occupies a particular location at the end of the European peninsula and at the crossroads of migration routes, few population genetic studies have been conducted so far with genome-wide data. In this study, we analyzed SNP-chip genetic data from 2 184 individuals born in France who were enrolled in two independent population cohorts. Using FineStructure, six different genetic clusters of individuals were found that were very consistent between the two cohorts. These clusters match extremely well the geography and overlap with historical and linguistic divisions of France. By modeling the relationship between genetics and geography using EEMS software, we were able to detect gene flow barriers that are similar in the two cohorts and corresponds to major French rivers or mountains. Estimations of effective population sizes using IBDNe program also revealed very similar patterns in both cohorts with a rapid increase of effective population sizes over the last 150 generations similar to what was observed in other European countries. A marked bottleneck is also consistently seen in the two datasets starting in the fourteenth century when the Black Death raged in Europe. In conclusion, by performing the first exhaustive study of the genetic structure of France, we fill a gap in the genetic studies in Europe that would be useful to medical geneticists but also historians and archeologists.

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