Old Horse Gives Up Its DNA – #365papers – 2017 – 54

#365papers for February 23, 2017

Orlando and 55 others, 2017, Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse: Nature, v. 499, p. 74-81.

What’s it about?

This paper discusses the results and implications of DNA analysis of a ~700 thousand-year-old horse fossil found in the Yukon Territory of Canada. This is the oldest horse fossil ever found with DNA. The results were compared with DNA from several modern horse breeds, donkeys, and Przewalski’s horse, the only non-domesticated horse breed.

Why does it matter?

The goals were to determine if Przewalski’s horse does represent a type of horse that has never known domestication, to see where this 700,000 year-old horse fit in with other horses, and to try to find our when the lineage that lead to modern horses (genus Equus), diverged from other types of horses. This helps us better understand what the common ancestor of all modern horses looked like and to better understand the process of evolution that lead to the variety of horses that live today.

Substantially, this paper puts the divergence of Equus from other horses around 4 million years ago, about 2 million years earlier than had originally been thought.

Why did I read this?

Horses.

Seriously, I became a paleontologist because of my love of horses. How can I resist a paper about fossil horses?