700,000-Year-Old Horse Genome Shatters Record for Sequencing of Ancient DNA:
By piecing together the genetic information locked inside a frozen, fossilized bone, scientists have deciphered the complete genome of an extinct prehistoric horse that roamed the Yukon more than 700,000 years ago. The work rewrites the evolutionary history of the horse and smashes the previous record for the oldest complete genome ever sequenced. In doing so, it redefines how far back in time scientists can travel using DNA sequences as their guide.
Every time a cowboy throws a leg over the saddle and gallops off on his horse, he’s riding on top of 4 million years of evolutionary history. But this history is mostly a mystery. We know surprisingly little about how natural selection and thousands of years of selective breeding by humans have shaped these animals on the genetic scale.
Horses were once considered a textbook example for the smooth transition of one species into another, a perfect illustration of Darwin’s theories. Ancient equine species — dog-sized animals with five toes – gradually evolved into towering, hooved thoroughbreds. Or so the story went. But with every fossil that was unearthed, a more tangled picture emerged.
Then DNA sequencing came along, allowing scientists to reconstruct how organisms change over time down to the resolution of single letters in the DNA code.
In the new study, a multinational team of scientists led by Ludovic Orlando and Eske Willerslev at the University of Copenhagen used what’s become a common approach: comparing the DNA of modern species to DNA recovered from fossil remains, in this case a fossil bone fragment found near Thistle Creek, Canada. By pushing DNA sequencing technology to its limits, they were able to rewind the evolutionary clock back further than ever before.
Full Article :http://www.wired.com/
By piecing together the genetic information locked inside a frozen, fossilized bone, scientists have deciphered the complete genome of an extinct prehistoric horse that roamed the Yukon more than 700,000 years ago. The work rewrites the evolutionary history of the horse and smashes the previous record for the oldest complete genome ever sequenced. In doing so, it redefines how far back in time scientists can travel using DNA sequences as their guide.
Every time a cowboy throws a leg over the saddle and gallops off on his horse, he’s riding on top of 4 million years of evolutionary history. But this history is mostly a mystery. We know surprisingly little about how natural selection and thousands of years of selective breeding by humans have shaped these animals on the genetic scale.
Horses were once considered a textbook example for the smooth transition of one species into another, a perfect illustration of Darwin’s theories. Ancient equine species — dog-sized animals with five toes – gradually evolved into towering, hooved thoroughbreds. Or so the story went. But with every fossil that was unearthed, a more tangled picture emerged.
Then DNA sequencing came along, allowing scientists to reconstruct how organisms change over time down to the resolution of single letters in the DNA code.
In the new study, a multinational team of scientists led by Ludovic Orlando and Eske Willerslev at the University of Copenhagen used what’s become a common approach: comparing the DNA of modern species to DNA recovered from fossil remains, in this case a fossil bone fragment found near Thistle Creek, Canada. By pushing DNA sequencing technology to its limits, they were able to rewind the evolutionary clock back further than ever before.
Full Article :http://www.wired.com/
No comments:
Post a Comment