From “Endangered horse has ancient origins and high genetic diversity, new study finds”(Eurekalert, September 7, 2011)., we
An endangered species of horse — known as Przewalski’s horse — is much more distantly related to the domestic horse than researchers had previously hypothesized, reports a team of investigators led by Kateryna Makova, a Penn State University associate professor of biology.
The scientists tested the portion of the genome passed exclusively from mother to offspring — the mitochondrial DNA — of four Przewalski’s horse lineages and compared the data to DNA from the domestic horse (Equus caballus). They concluded that, although previous scientists had assumed that Przewalski’s horse and the domestic horse had diverged around the time that horses were domesticated — about 6,000 to 10,000 years ago — the real time of the two species’ divergence from one another is much more ancient.
The data gleaned from the study also suggest that present-day Przewalski’s horses have a much more diverse gene pool than previously hypothesized.
It’s interesting how often genomes are full of surprises.
Makova added that, although the two species diverged well over 100,000 years ago, they have interbred periodically since then. “Also fortunate is the fact that conservationists in the second half of the 20th century realized how grave the situation was for the Przewalski’s horse. They not only began new breeding efforts and built wildlife reserves in California and the Ukraine, but they also made sure to avoid inbreeding among close relatives,” Makova said. “For this reason, the present-day population has managed to remain healthy by retaining substantial genetic diversity.”
So it’s not clear to what extent Przewalski’s horse really is a separate species. But if people thought so, they were more likely to take action to preserve it, and we can be glad for that. Follow UD News at Twitter!