Population structure, gene flow, and sex-biased dispersal in the reticulated flatwoods salamander (): Implications for translocations.

Understanding patterns of gene flow and population structure is vital for managing threatened and endangered species. The reticulated flatwoods salamander () is an endangered species with a fragmented range; therefore, assessing connectivity and genetic population structure can inform future conservation. Samples collected from breeding sites ( = 5) were used to calculate structure and gene flow using three marker types: single nucleotide polymorphisms isolated from potential immune genes (SNPs), nuclear data from the major histocompatibility complex (MHC), and the mitochondrial control region. At a broad geographical scale, nuclear data (SNP and MHC) supported gene flow and little structure (  = 0.00-0.09) while mitochondrial structure was high (Φ = 0.15-0.36) and gene flow was low. Mitochondrial markers also exhibited isolation by distance (IBD) between sites ( = 0.01) and within one site ( = 0.04) while nuclear markers did not show IBD between or within sites ( = 0.17 and  = 0.66). Due to the discordant results between nuclear and mitochondrial markers, our results suggest male-biased dispersal. Overall, salamander populations showed little genetic differentiation and structure with some gene flow, at least historically, among sampling sites. Given historic gene flow and a lack of population structure, carefully considered reintroductions could begin to expand the limited range of this salamander to ensure its long-term resilience.