The Dana Point offspring did better when they were bred with other populations, however. “But normally natural selection does a good job of keeping harmful mutations at low frequency, so they’re rare in the population.” When populations get really small, though, natural selection doesn’t work so well, she said. “All populations have mutations in them,” Wilder said. Researchers believe the reason the Dana Point population’s genetics decreased has to do with genetic load - the buildup of harmful mutations in the genome. They found that the pocket mice from Dana Point - the smallest population and the one suffering the most from inbreeding - became less and less represented in the genetics of breeding program over time. “The initial reason was to have a source of individuals to use for reintroduction in parts of their range where they’re no longer found,” she said. In a study published in Conservation Genetics, Wilder and her colleagues looked at microsatellite and mitochondrial DNA of the individuals bred in the zoo’s program to help them determine the best ways to reintroduce the animals to the wild. The San Diego Zoo began a conservation breeding program for the species in 2012, taking individuals from each population as founders. “Then, they were rediscovered in the ’90s, and emergency listed under the Endangered Species Act.”īy then, only three populations remained: Two at Marine Corps Base Camp Pendleton and one about 36 miles away in Dana Point, a coastal city in Orange County, separated from the others by urban development. “They were thought to be extinct for a while,” she said. Its range used to stretch from the Mexican border to Los Angeles, Wilder said, but around the 1930s, many of its populations began to disappear. “I think it’s actually more closely related to beavers in some phylogenies.” “It’s called the Pacific pocket mouse because it looks like a mouse,” said Aryn Wilder, a senior researcher at San Diego Zoo Global who led a recent study on the rodent. A critically endangered subspecies of the little pocket mouse, it’s found in only three isolated locations within about 3 miles of the southern California coast. Researchers are delving into the genomes of Pacific pocket mice to help inform conservationists about the best ways to recover the federally endangered species, which has only three populations left in the wild.ĭespite its name, the Pacific pocket mouse ( Perognathus longimembris pacificus) is not closely related to mice at all. Researchers looked at the genomes of endangered Pacific pocket mice.

Jacumba pocket mouse habitat