Evaluating Genetic Diversity to Save Endangered Species

As endangered species become fragmented into smaller and smaller populations, these animals are susceptible to loss of genetic diversity and harmful genetic mutations. In 2012, San Diego Zoo researchers began a captive breeding program to prevent the extinction of one such species, the Pacific pocket mouse. These rodents now are isolated to only three small habitat patches in southern California. Five generations of captive breeding saw steady growth and increased genetic diversity of captive-born mice. However, low reproductive output of some animals was traced back to the genetics of one of the founding conservation populations. This has raised questions about how best to manage harmful mutations while restoring diversity and promoting population growth to save an endangered species. Researchers will examine the genomes of hundreds of captive and wild-born Pacific pocket mice, track genetic variants over time and quantify their effect on health and reproduction. Findings will help wildlife researchers better manage genetic variation in Pacific pocket mice and will serve as a valuable model for other endangered species when captive breeding and genetic rescue are necessary to prevent extinctions.