Wild mice are isolated, but may have the genetic diversity to adapt to high temperatures
A tiny mouse on the verge of extinction on the California coast might be able to adapt to a warmer world, although it could use a little help.
Genetic analyzes of critically endangered Pacific pocket mice suggest the species has the genetic diversity to adapt to climate changereport the researchers on April 17 in Scientific advances. But urbanization has isolated the remaining animals, and conservation efforts may be needed to help spread genes linked to acclimation.
The Pacific pocket mouse range (Perognathus longimembris pacificum) once spanned the southern California coast from Los Angeles to Mexico. The creature remained undetected for more than two decades, but was rediscovered in the early 1990s, receiving protection under the U.S. Endangered Species Act. There are only three small groups left south of Los Angeles.
Endangered species may have difficulty adapting to environmental changes, in part because inbreeding can destroy the genetic diversity necessary for a species to evolve. All three wild populations of Pacific pocket mice have declined due to habitat loss, says Erik Funk, a conservation geneticist at the San Diego Zoo Wildlife Alliance. In 2012, researchers launched a conservation program at the zoo that breeds individuals from all three groups and releases their offspring into the Laguna Coast Wilderness Park in Laguna Beach, California.
To find out how resilient wild and reintroduced Pacific pocket mice might be to climate change, Funk and his colleagues analyzed the genetic blueprints of mice collected over nearly a century. Even though modern mice are more inbred, 14 genes that could help the species adapt to climate change retain some diversity. Some genes are linked to heart function, which could help animals calm down.
It’s unclear whether the three wild groups could individually adapt to a warmer world, but genetic analyzes showed that released animals with mixed genes could already adapt to the wild park’s climate. “The real benefit to this liberated population is that they’re all mixed together,” Funk says. “In wild populations, there is variation in one population, variation in another. We think the greatest benefits come when we can combine all of that diversity.”
It is unknown how many Pacific pocket mice remain. Disasters such as floods or severe droughts can push vulnerable species further towards extinction. And as more and more animals perish, the remaining genetic diversity diminishes. “Once lost,” Funk says, “it cannot be brought back.”
