Friday, August 8, 2008

PS 88-156: Genetic structure of striped skunk (Mephitis mephitis) in an urban landscape

Jason A. Sumners1, Randy W. DeYoung1, Denise M. Ruffino2, and Scott E. Henke1. (1) Texas A&M-Kingsville, (2) USDA-APHIS-Wildlife Services

Background/Question/Methods

The striped skunk is widely distributed in North America and a common inhabitant of urban areas. Striped skunks represent a reservoir and vector for the transmission of diseases that pose a significant human health risk, including rabies and the parasite Toxoplasma gondii. Information on population structure and movements of striped skunks will assist in the management of disease issues within urban landscapes. Here we present a spatial analysis of striped skunk population structure within greater Houston, Texas, USA, based on 7 microsatellite DNA markers amplified in 102 adult striped skunks.

Results/Conclusions

We detected weak genetic structure over the entire data set (FST = 0.031). An analysis of spatial autocorrelation based on Moran’s I revealed a large neighborhood size, where genetic structure was a function of geographic distance between individuals.  Samples collected within 8-10 km were not genetically independent. Disparity of assignment index and FST values between males and females supports a male bias in dispersal. Estimates of Nm calculated from pairwise FST among 3 sampling sites ranged from 6.2-10.6 migrants per generation. Although this highly developed urban landscape is bisected by major highways with high traffic volume (e.g., Interstate 10 and US 59), we found no evidence for unique genetic clusters that might indicate barriers to dispersal.  Our results indicate that local populations of urban skunks in this region encompass a relatively large geographic area.  Thus, management of disease risk will require spatially extensive efforts.