Mapping genes from 700 000 years ago

2013-06-26 23:00
Two pieces of a 700 000-year-old horse metapodial bone.

Two pieces of a 700 000-year-old horse metapodial bone. (AP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Helsinki - From a tiny fossil bone found in the frozen Yukon, scientists have deciphered the genetic code of an ancient horse about 700 000 years old — nearly 10 times older than any other animal that has had its genome mapped.

Scientists used new techniques and computing to take DNA from a 5-inch fossil fragment - most of which was contaminated with more modern bacteria -and get a good genetic picture of an ancestral horse. The work was published on Wednesday in the journal Nature and discussed at a science conference in Helsinki.

The research gives a better insight into the evolution of one of the most studied mammals. Perhaps more importantly, it opens up new possibilities for mapping the genetic blueprints of all sorts of ancient animals from early human ancestors to mastodons to mammoths to bison, said study lead authors Ludovic Orlando and Eske Willerslev of the University of Copenhagen.

This "is breaking the time barrier", Willerslev said.

The previous oldest animal fossil genetically mapped had been an ancient relative of Neanderthals called the Denisovans, from about 75 000 years ago, found in a Siberian cave.

The ancient horse was probably about the size of current Arabian horses, the researchers said. It didn't have the same genes for large muscles that make today's breeds good for racing, and it was larger than researchers once thought, Orlando and Willerslev said.

The new mapping techniques, which involve all sorts of technical changes, could be used not just with fossils from frozen areas like Canada's Yukon and Russia's Siberia, but also from more temperate climates, and may eventually allow researchers to map animal genomes from 1 million years ago, Orlando said.

Ross MacPhee, curator of mammals at the American Museum of Natural History, who wasn't part of the research, said the accomplishment suggests "there's no reason in substance why we couldn't go back further".

"I think it's cool," said another outside expert, Edward Rubin, who heads the US Department of Energy's Joint Genome Institute and has deciphered Neanderthal and cave bear DNA.

"We can always keep our fingers crossed that [DNA from] an ancient hominid will be found in one of those environments that have been cold," perhaps even the last common ancestor of Neanderthals and modern humans, he said.

Orlando and Willerslev said it doesn't have to be that cold, but much of the most ancient human development was in Africa where the hotter climate makes DNA disintegrate faster. Still, there were enough hominids in temperate climates to give hope for older genome sequencing of some of our ancestors, they said.

There was a lot of junk in the Yukon fossil that wasn't horse but bacteria, Orlando said. He said for every 200 DNA molecules they sequenced, only one was from the horse.

The research estimated that the evolutionary tree split that led to horses on one branch and donkeys on the other happened about 4 million years ago.

The analysis also found new evidence that an endangered animal called the Przewalski's horse, found in Mongolia and China, is the last surviving wild horse. It is genetically distinct from domestic horses.

Read more on:    animals  |  genetics

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.
NEXT ON NEWS24X

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
8 comments
Comments have been closed for this article.

Inside News24

 
/News

Book flights

Compare, Book, Fly

Traffic Alerts
Traffic
There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.




Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.