Genetic population structure within and between beaver (Castor Canadensis) populations in illinois

Abstract

Mating behavior and social structure can influence genetic structure within and between populations, yet most studies focus on highly kin-structured, polygynous species. The North American beaver (Castor canadensis) is socially monogamous; however, examination of recent genetic data suggests that this species may be opportunistically promiscuous. We used 7 microsatellite loci to quantify genetic structure within and between 2 beaver populations in Illinois. An analysis of molecular variance revealed significant genetic subdivision among breeding groups in southern Illinois (FST = 0.086, P < 0.001), whereas regional genetic subdivision was evident in central Illinois (F ST = 0.037, P < 0.001). Overall FST between populations also was significant (0.068 ± 0.012 SE, P < 0.001). Bayesian clustering assigned individuals from the 2 geographic sampling regions into 2 distinct genetic clusters with 70% of individuals assigned to 1 of the 2 clusters. Migration between populations was low at 0.16 individuals/generation (confidence interval = 0.0079-0.33). Estimates of population subdivision, cluster analysis, and dispersal indicate that these populations are genetically distinct, but are connected by infrequent dispersal. © 2009 American Society of Mammalogists.