Genetic Variation of Pronghorn Across U.S. Route 89 and State Route 64

This study investigated whether highways acted as barriers to gene flow for pronghorn in northern Arizona. DNA samples from 132 pronghorn were analyzed using eight polymorphic microsatellite loci. Samples represented animals living on opposite sides of US Route 89 (US 89) and State Route 64 (SR 64). Two different modeling approaches indicated that both US 89 and SR 64, and to a lesser extent US Route 180 (US 180), acted as barriers to gene flow. The genetic structuring caused by highways, especially across US 89, is consistent with behavioral data that demonstrated pronghorn rarely cross this highway. This study found no evidence of inbreeding or reduced genetic variation in any of the populations examined, but those effects may take longer to appear. Based on these results, the researchers recommend future genetic monitoring of these populations or assessment of genetic variation across highways with larger traffic volumes or longer histories to determine whether the barrier effects documented here lead to loss of genetic diversity.