Document Type

Greater Yellowstone Ecosystem Report

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Yellowstone National Park's northern range is home to a geographically isolated population of pronghorn (Antilocapra americana) greatly reduced from historic levels of abundance. The genetic consequences of demographic declines in this population over the past 150 years are unknown, and the rates of genetic exchange among this and other populations in the Yellowstone basin are also unknown. We used 18 nuclear DNA microsatellite loci and noninvasively collected fecal samples from 73 individuals to quantify basic population genetic parameters and gene flow within and among the Yellowstone pronghorn population, a new population in the Paradise Valley, and a large population near Livingston, MT. Evidence for a genetic bottleneck in Yellowstone was strong based on several tests of heterozygote excess (Wilcoxon tests P≤ 0.033) and the relative ratio of allele richness to allele size range (M =0.283). However, mean population heterozygosity was high (HO = 0.665), and no indications of inbreeding were detected. Gene flow from elsewhere in the Yellowstone basin to Yellowstone National Park is extremely low. However, emigration from Yellowstone to the Paradise Valley population is high (26.7%), reinforcing conclusions based on behavioral data that this new population was founded by Yellowstone individuals. Despite years of population decline and genetic isolation, Yellowstone pronghorn appear to retain substantial genetic diversity.