1 Citation 407 Views 98 Downloads
Spatial patterns of genetic variation can help understand how
environmental factors either permit or restrict gene flow and create
opportunities for regional adaptations. Organisms from harsh environments
such as the Brazilian semiarid Caatinga biome may reveal how severe
climate conditions may affect patterns of genetic variation. Herein we
combine information from mitochondrial DNA with physical and environmental
features to study the association between different aspects of the
Caatinga landscape and spatial genetic variation in the whiptail lizard
Ameivula ocellifera. We investigated which of the climatic, environmental,
geographical and/or historical components best predict: (1) the spatial
distribution of genetic diversity, and (2) the genetic differentiation
among populations. We found that genetic variation in A. ocellifera has
been influenced mainly by temperature variability, which modulates
connectivity among populations. Past climate conditions were important for
shaping current genetic diversity, suggesting a time lag in genetic
responses. Population structure in A. ocellifera was best explained by
both isolation by distance and isolation by resistance (main rivers). Our
findings indicate that both physical and climatic features are important
for explaining the observed patterns of genetic variation across the xeric
Caatinga biome.
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