Bovine mtDNA Discovered in North American Bison Populations

North American bison (Bison bison), which once numbered in the millions, were nearly extirpated by the late 1800s. The present recovery of the bison is owed to ranchers who collected bison scattered across the prairies for the purpose of establishing founding stocks (Allen 1877; Garretson 1934; Rorabacher 1970; Dary 1974; Ogilvie 1979). By 1889 there were an estimated 200 bison in Yellowstone National Park, Wyoming, 550 bison in Wood Buffalo National Park (Alberta and Northwest Territories; WBNP), and only 340 bison held on private ranches and wild herds (Jenning & Hebbing 1983). By the 1900s the bison population in Yellowstone and WBNP had dropped to 22 and 250 animals, respectively, because of poaching. Bison used to restock parks in both the United States and Canada were selected from the small surviving nucleus of animals. Today bison populations are flourishing, and more than 18,696 bison can be found in the North American parks alone (Walker 1993). Consequently, conservation efforts have moved from increasing bison numbers to accumulating information on the genetic diversity and relatedness of populations. In the process of constructing a phylogeny for North American bison from mitochondrial DNA (mtDNA), we discovered a bovine (Bos taurus) haplotype (mitochondrial genotype) in the Custer State Park (CSP) herd of South Dakota. The discovery of the bovine haplotype prompted a survey for bovine haplotypes among eight other park populations of bison. Because bison were exchanged between several established park populations, the possibility exists that bovine genes have spread throughout North American bison populations. Park populations that did not ex-