PRZEWALSKI’S HORSE DNA ANALYZED

Although the Przewalski’s horse is popularly regarded as the world’s last remaining wild horse, a recently completed genetic analysis shows that as much as 25 percent of its DNA comes from domesticated breeds.

Discovered on the Asian steppes in the 1870s, the a global consortium of researchers from 21 institutions led by Ludovic Orlando, PhD, of the University of Copenhagen sequenced the DNA of 11 Przewalski’s horses, five museum specimens of the species and 28 domesticated horses. The use of museum the genetic lines of domestic horses and Przewalski’s horses diverged about 45,000 years ago, but the populations continued to mix intermittently, even after horses were domesticated nearly 5,500 years ago.

In addition, by the early 20th century, when the entire Przewalski’s population was in captivity, domestic horses contributed significantly to the surviving lineages. Among the study samples, as much as one quarter of the genomes in the Przewalski’s are made up of gene variants inherited from domestic horses.

Founded from no more than a dozen individuals, today’s Przewalski’s horse population numbers more than 2,000, including several bands living in wild reintroduction preserves in Mongolia. They are considered endangered by the International Union for Conservation of Nature, but, says Orlando, they “clearly represent a success story in conservation biology.”

Domesticated horses contributed genetic material that may have helped the ancient species survive, but the DNA of Przewalski’s horses is distinct. The researchers say the biggest differences between Przewalski’s horse DNA and that of domesticated horses were seen in genes governing metabolism, reproduction, muscle contraction, behavior, cardiac disorders and signaling pathways within the nervous system.--- Diane Coffman

Founded from no more than a dozen individuals, today’s Przewalski’s horse population numbers more than 2,000, including several bands living in wild reintroduction preserves in Mongolia.