Genetic Effects of California Drought on Helix aspersa populations at Pepperdine University

The garden snail, Helix aspersa, is an introduced species distributed throughout southern California, as well as other regions of the United States. The distribution of garden snails on Pepperdine University’s Malibu campus is influenced by access to water, and prior to the rain this year, the past drought has impacted snail populations in some regions of the campus. In an effort to evaluate genetic impact of the drought on snail populations, we compared patterns of genetic variation in a pre-drought populations sampled in 2008 to the same populations sampled in 2016. Microsatellite loci were used to compare genetic variation during these two time periods. Given the short generation time observed for snails, we hypothesized that these two time periods should show high levels of genetic differentiation. All of our comparisons showed significant genetic differences among the various pairwise comparisons performed, thus supporting our hypothesis