Meeting Abstract
Copperhead snakes (Agkistrodon contortrix) are widely distributed in the United States and have been divided into five subspecies. Observation of regional behavioral differences in striking behavior within Arkansas copperheads led us to look for differences in the venom of the subspecies of copperheads. Because venom is a key adaptation in viper food acquisition, differences in the abundance, form, and activity of various venom components are likely to lead to differences in prey capture behavior. Phospholipase A2 (PLA2), a myotoxic component of copperhead venom, is an important protein in many snake venoms either as an enzymatic component or as a toxin. The aim of this study was to isolate and sequence the genomic PLA2 genes from all five subspecies to understand whether these genes have diversified within the species, and if so what effect the variations might have on the protein. We isolated and sequenced PLA2 genes from individuals of all five subspecies, and found distinct differences in the nucleotide sequences and the predicted amino acid sequences between the subspecies. Some of the differences correlate with known differences in PLA2 potency. A phylogenetic analysis of the PLA2 sequences allowed us to examine a snake of unknown subspecific designation from an area of integration in the Ozarks of Arkansas. This snake showed sequences that closely associated with sequences from two different subspecies. In addition, the sequences we obtained allow us to test whether these genes are evolving through drift, selection, or a combination of the two.
