Phylogeography of the cottonmouth, Agkistrodon piscivorus, using AFLP and venom protein profiles.

Abstract

The objective of this study was to examine population structure in cottonmouths (Agkistrodon piscivorus) using Amplified Fragment Length Polymorphism (AFLP) and compare genetic and venom protein profiles in Texas. AFLP profiles using 622 fragments were generated for 105 individuals to understand the level of variation within Agkistrodon. In Texas, there was a significant lack of gene flow detected and support for the isolation of Concho Valley individuals. Cottonmouths showed the greatest genetic variation when compared to other Agkistrodon species but there was not complete support for two species of cottonmouths as currently proposed. RP-HPLC was used to examine venom protein profiles in 86 Texas cottonmouths. Relative peak heights were analyzed using PCA and the MANOVA demonstrated separation of populations based on profiles (p<0.001). Genetic and venom variation did not follow the same pattern indicating that there may be other selection pressures acting on the venom proteins.