Graduate project

Investigating geographic isolation in the Sutter Buttes using comparative Northern Pacific Rattlesnake (Crotalus oreganus oreganus) venom proteomics

Geographic variation research is an important topic of study, providing insight into trends of organismal origin, dispersal and evolution. By virtue of investigating these trends, this research also exposes areas where conservation efforts are needed to prevent the decline of vulnerable populations. The Sutter Buttes are an isolated patch of mountainous habitat in the middle of the Sacramento Valley. The buttes are separated from the Sierra Nevada by a minimum of nine miles to the east and from the Coast Range by ### miles to the west . The isolation of organisms in the Sutter Buttes has been proposed numerous times, and has also been the subject of research on several other projects looking at the relationship between populations of organisms in the Sutter Buttes and those in neighboring mountain ranges. This project utilizes liquid chromatography and mass spectrometry to separate and identify proteins in the venom of multiple individuals of northern Pacific rattlesnake (Crotalus oreganus oreganus) from two regions: the Sutter Buttes and the nearby Sierra Nevada. I provide a whole venom profile for this subspecies of western rattlesnake, and identify specific proteins found to be significantly different in abundance between populations of C. o. oreganus inhabiting the two regions. Significant differences in the relative abundance of three venom proteins provide evidence of restricted connectivity between the two neighboring regions, indicating geographic isolation for certain organisms inhabiting the Sutter Buttes. This has important implications for local adaptation and conservation of unique geographic variants in rattlesnakes.