Genetic Variation and Gene Flow at the Range Edge of Two Softshell Turtles

Abstract

Abstract The movement of riverine animals can greatly impact the distribution of genetic variation among populations. The limited dispersal of reptiles and amphibians can produce significant genetic differentiation among geographically proximate populations. Studying the factors that contribute to genetic variation at the poleward edge of species' ranges may be particularly important as ranges shift in response to climate change. We examined physical movement and the distribution of genetic variation among populations of two riverine softshell turtle species, Apalone spinifera and Apalone mutica in Minnesota. We sequenced the mitochondrial control region and genotyped six variable microsatellite loci for 220 turtles across three river systems. Using radiotelemetry, we monitored aquatic movement and tested for sex differences in movements among 19 turtles. We found no evidence of genetic differentiation at geographic scales yielding significant differentiation in other freshwater turtles, a trend that may ...