Wednesday, October 05, 2005

673: How A Zebra Lost Its Stripes: Rapid Evolution Of The Quagga

How A Zebra Lost Its Stripes: Rapid Evolution Of The Quagga:

In the past, the quagga has alternatively been described as a species and a subspecies of the Plains zebra.These researchers asked how and when the quagga diverged from all the remaining related horses, zebras, and asses. They compared the genetics, coat color and habitats of existing zebras with related extinct species.

The mitochondrial DNA markers from 13 museum specimens, including the only skeleton in museum collections, which is at Yale's Peabody Museum of Natural History, showed that quagga likely diverged from Plains zebra about 120,000 to 290,000 years ago during the Ice Age. These results suggest that the quagga descended from a population of plains zebras that became isolated and the distinct quagga body type and coloring evolved rapidly.

This study reveals that the Ice Age was important not just in Europe and North America, but also in Africa.

"The rapid evolution of coat color in the quagga could be explained by disrupted gene flow because of geographical isolation, an adaptive response to a drier habitat, or a combination of both of the two forces," said Caccone.
Thanks to afarensis for the tip.