scholarly journals Species-Wide Genetic Variation and Demographic History ofDrosophila sechellia, a Species Lacking Population Structure

Genetics ◽  
2009 ◽  
Vol 182 (4) ◽  
pp. 1197-1206 ◽  
Author(s):  
Delphine Legrand ◽  
Maud I. Tenaillon ◽  
Pat Matyot ◽  
Justin Gerlach ◽  
Daniel Lachaise ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Demographic History

scholarly journals Demographic modeling informs functional connectivity and management interventions in Graham’s beardtongue

2021 ◽  
Author(s):  
Matthew R. Jones ◽  
Daniel E. Winkler ◽  
Rob Massatti
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Functional Connectivity ◽  
Isolation By Distance ◽  
Management Practice ◽  
Demographic History ◽  
Principal Component ◽  
Management Options ◽  
Demographic Modeling ◽  
Management Interventions

AbstractFunctional connectivity (i.e., the movement of individuals across a landscape) is essential for the maintenance of genetic variation and persistence of rare species. However, illuminating the processes influencing functional connectivity and ultimately translating this knowledge into management practice remains a fundamental challenge. Here, we combine various population structure analyses with pairwise, population-specific demographic modeling to investigate historical functional connectivity in Graham’s beardtongue (Penstemon grahamii), a rare plant narrowly distributed across a dryland region of the western US. While principal component and population structure analyses indicated an isolation-by-distance pattern of differentiation across the species’ range, spatial inferences of effective migration exposed an abrupt shift in population ancestry near the range center. To understand these seemingly conflicting patterns, we tested various models of historical gene flow and found evidence for recent admixture (~ 3400 generations ago) between populations near the range center. This historical perspective reconciles population structure patterns and suggests management efforts should focus on maintaining connectivity between these previously isolated lineages to promote the ongoing transfer of genetic variation. Beyond providing species-specific knowledge to inform management options, our study highlights how understanding demographic history may be critical to guide conservation efforts when interpreting population genetic patterns and inferring functional connectivity.

scholarly journals Ecological opportunities and specializations shaped genetic divergence in a highly mobile marine top predator

2014 ◽  
Vol 281 (1795) ◽  
pp. 20141558 ◽  
Author(s):  
Marie Louis ◽  
Michael C. Fontaine ◽  
Jérôme Spitz ◽  
Erika Schlund ◽  
Willy Dabin ◽  
...  
Keyword(s):  
Population Structure ◽  
Mediterranean Sea ◽  
Environmental Changes ◽  
Demographic History ◽  
World Ocean ◽  
Ecological Niches ◽  
Morphological Divergence ◽  
Evolutionary Diversification ◽  
The Mediterranean ◽  
Population Demographic

Environmental conditions can shape genetic and morphological divergence. Release of new habitats during historical environmental changes was a major driver of evolutionary diversification. Here, forces shaping population structure and ecotype differentiation (‘pelagic’ and ‘coastal’) of bottlenose dolphins in the North-east Atlantic were investigated using complementary evolutionary and ecological approaches. Inference of population demographic history using approximate Bayesian computation indicated that coastal populations were likely founded by the Atlantic pelagic population after the Last Glacial Maxima probably as a result of newly available coastal ecological niches. Pelagic dolphins from the Atlantic and the Mediterranean Sea likely diverged during a period of high productivity in the Mediterranean Sea. Genetic differentiation between coastal and pelagic ecotypes may be maintained by niche specializations, as indicated by stable isotope and stomach content analyses, and social behaviour. The two ecotypes were only weakly morphologically segregated in contrast to other parts of the World Ocean. This may be linked to weak contrasts between coastal and pelagic habitats and/or a relatively recent divergence. We suggest that ecological opportunity to specialize is a major driver of genetic and morphological divergence. Combining genetic, ecological and morphological approaches is essential to understanding the population structure of mobile and cryptic species.

scholarly journals Determining Whether Geographic Origin and Potato Genotypes Shape the Population Structure of Phytophthora infestans in the Central Region of Colombia

2019 ◽  
Vol 109 (1) ◽  
pp. 145-154
Author(s):  
Sandra Catalina Chaves ◽  
María Camila Rodríguez ◽  
María Fernanda Mideros ◽  
Florencia Lucca ◽  
Carlos E. Ñústez ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Phytophthora Infestans ◽  
Central Region ◽  
Geographic Origin ◽  
Geographic Area ◽  
Potato Cultivars ◽  
Clonal Lineage ◽  
Host Genotype ◽  
Genetic Population

Pathogen variation plays an important role in the dynamics of infectious diseases. In this study, the genetic variation of 279 Phytophthora infestans isolates was assessed using a combination of 12 microsatellite simple-sequence repeat markers. Isolates were collected from 11 different potato cultivars in 11 different geographic localities of the central region of Colombia. The objective of this study was to determine whether populations were differentiated by host genotype or geographic origin. Within a single clonal lineage, EC-1, 76 genotypes were detected. An analysis of molecular variance attributed most of the variation to differences within host genotypes rather than among the host genotypes, suggesting that host cultivars do not structure the populations of the pathogen. Furthermore, the lack of a genetic population structure according to the host cultivar was confirmed by all of the analyses, including the Bayesian clustering analysis and the minimum spanning network that used the Bruvo genetic distance, which suggested that there are no significant barriers to gene flow for P. infestans among potato cultivars. According to the geographic origin, the populations of P. infestans were also not structured, and most of the variation among the isolates was attributed to differences within localities. Only some but not all localities in the north and west of the central region of Colombia showed some genetic differentiation from the other regions. The absence of sexual reproduction of this pathogen in Colombia was also demonstrated. Important insights are discussed regarding the genetic population dynamics of the P. infestans populations of the central region of Colombia that were provided by the results. In Colombia, there is a high genetic variation within the EC-1 clonal lineage with closely related genotypes, none dominant, that coexist in a wide geographic area and on several potato cultivars.

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