Scanning the Genome of Mexican Wolves to Improve their Captive Breeding and Reintroduction Program

The Mexican wolf (Canis lupus baileyi) was extirpated from the southwestern US and Mexico by 1980. To preserve the Mexican wolf population for future reintroductions, a captive breeding program was established in 1981. This certified captive population originated from three individual wolves (founders), while two additional captive populations were each established from two individuals. Over time, however, the small number of founders from each population resulted in a high level of inbreeding. Inbreeding causes individuals to express slightly deleterious traits, thereby reducing the fitness of the population (called inbreeding depression). To mitigate this, the three captive wolf lineages were merged in 1995. The merger led to an increase in fitness traits, known as genetic rescue, in cross-lineage wolves. In 1998, the first reintroduction of wolves began. Currently, the free-ranging wolf population numbers approximately 40 individuals. Studies using up to 20 genetic markers called microsatellites have measured levels of relatedness and genetic variation among wolves. Despite these studies, numerous concerns remain, including: the purity of founders (whether or not they have mixed with domestic dogs or coyotes in the past), the extent of inbreeding in the captive and wild populations, the current distribution of genetic variation from the founders, and minimizing inbreeding depression. We are examining these concerns using genomic technologies developed for the domestic dog. We are analyzing ~100 Mexican wolves for more than 172,000 additional genetic markers called SNPs (single nucleotide polymorphisms). This presentation will highlight the basic methodologies of the project and provide some preliminary results.