SOURCE: News.sciencemag.org by Gisela Telis
Prehistoric Takhi reintroduced into Outer Mongolia ~ photo by Terry Fitch of Wild Horse Freedom Federation
Scientists have sequenced the oldest genome to date—and shaken up the horse family tree in the process. Ancient DNA derived from a horse fossil that’s between 560,000 and 780,000 years old suggests that all living equids—members of the family that includes horses, donkeys, and zebras—shared a common ancestor that lived at least 4 million years ago, approximately 2 million years earlier than most previous estimates. The discovery offers new insights into equine evolution and raises the prospect of recovering and exploring older DNA than previously thought possible.
“There’s no question this is a landmark study,” says David Lambert, an evolutionary biologist at Griffith University in Australia who was not involved in the work. “It’s well beyond the time period where I thought we had any prospect of getting a genome.”
The study began with a walk in the permafrost. Evolutionary biologist Eske Willerslev of the University of Copenhagen joined a team of geologists on a 2003 expedition in Canada’s Yukon Territory. The group was exploring a site that holds ice and volcanic ash that date back more than 700,000 years. There, Willerslev spotted a piece of bone jutting from the frozen ground and decided he would study it.
The fossil, a fragment of horse leg bone, was too old for radiocarbon dating, but Willerslev estimated, based on its location in the permafrost, that it was between 560,000 and 780,000 years old. He and an international team of colleagues then set about scouring the fragment for any trace of collagen or other material that could harbor the ancient horse’s DNA.
The odds were against the team. No DNA had been salvaged and sequenced from a fossil more than 130,000 years old (that was a polar bear jawbone), and theoretical estimates put the upper limit of DNA survival at about 1 million years. Yet, a preliminary analysis of the sample hinted that it might contain a few remaining pockets of collagen and blood. Using the detailed, time-consuming process with which Willerslev sequenced an ancient human’s DNA in 2010, the researchers were able to reconstruct the equid’s genetic code. For comparison, they also sequenced the genomes of a Late Pleistocene horse that lived about 43,000 years ago, a contemporary donkey, five different domestic horse breeds, and a Przewalski’s horse, which is considered the world’s only remaining wild horse and a source of controversy. Genetically speaking, other so-called wild horses—for example, the mustangs of the American West—are simply domesticated horses gone feral. Przewalski’s horse is thought to be genetically distinct, but some experts have expressed doubt over whether this cousin of the domesticated horse carries some domesticated horse genes.
As for what the ancient horse looked like, Willerslev says that he was large but not as tightly muscled as a modern horse. “This was a tall guy, on the order of Arabian horses,” he says. “But I don’t think he’s something Napoleon would ride into town on.”
The sequenced genome offers a glimpse at the ancient horse and how equine genes have evolved. Genes that are involved in immunity, the sense of smell, and muscle development have all changed significantly since this ancient horse roamed the Yukon, Willerslev says.
Beyond its implications for equine evolution, the study pushes the envelope for ancient DNA research, Willerslev says. “It was not that long ago that people in the field of ancient DNA would have said you can’t retrieve data from something this old, but here we have a whole genome.”
Lambert agrees that the team’s work creates new possibilities for DNA research, including applying the technique to ancient human fossils to gain a clearer picture of human evolution. “This study will encourage people to say, ‘Maybe we should give this a go,’ ” he says. “It makes you wonder if a million-year-old genome would be possible.”
Related Articles
- 700,000-Year-Old Horse Becomes Oldest Creature With Sequenced Genome (rtfitchauthor.com)
- Yukon gold mine yields ancient horse fossil (eurekalert.org)
- Horse DNA oldest by 500,000 years (bbc.co.uk)
- Ancient horse is oldest creature to reveal DNA sequence – Los Angeles Times (latimes.com)
- Mapping genes of a horse from 700,000 years ago (metronews.ca)
Categories: Horse News
Straight from the Horse's Heart 
I subscribe to BBC news so I saw this earlier. Lets hope this puts to rest the morons out there that are always writing comments about the Mustangs not being native to North America or horses in general not being native. Its unlikely that any of them would understand what the scientists were talking about anyway.
LikeLike
How wonderful this is. It is inspiring to have deep science looking at wild horses and this is the reintroduced horse that RT and Terry saw in Mongolia. A rare and old lineage it has. A wild horse to celebrate!
LikeLike
HA, I like that comment Barb, this is huge and what a wonderful fine, WOW so exciting… These scientist must be elated to be able to have this DNA and to make this unbelievable fine for our horses history for all of us, yup horses are NOT native alright, just keeps piling up on them all finally, but I am sure pro slaughter will come up with some other bunch of lies…? We’ll see?
LikeLike
We certainly have the limits of our knowledge proven to us all the time. Good news, let’s see them spin it.
LikeLike
This is so Cool!!…Really nice Evidence… and great that you both saw these horses in Mongolia…..
LikeLike
absolutely fascinating, alters everything we thought before.
LikeLike
Adam and eve must have wondered at them also.
LikeLike
The University of Copenhagen’s research team on large mammal extinction published an article in the December 29, 2009 Procedings of the National Academy of Sciences containing a table showing that the species of ancient horse in Alaska 7,600 years ago is a 98% to 100% match to Equus caballus. However, because the information is limited to one table within the article and another table in the Supporting Information, researchers cannot find the article using ordinary search terms.
The evidence that our horses and burros are North American native species has been published now for three and a half years. The words invasive, non-native, feral, pest, exotic, alien species are not expressions of a bad attitude. These are the words of a government policy that made its way from international law into federal agency guidelines after President Bill Clinton signed the 1992 Convention on Biological Diversity. The President’s signature allowed federal agencies to implement this international policy into U. S. regulations without a word ever entering into Congressional debate.
The University of Copenhagen found that North American horses had no genetic differences that would have put them any more at risk for extinction than the horses that were found in Europe or Asia. Since the climate in North America was similar to that of Northern Europe where horses survived the warming period after the last large glacial period, researchers also found that climate change could not explain the extinction of the North American horse. Many of the plants that grew in the areas where horses were found in North America 7,600 years ago. So, every piece of the Clinton-Gore-let’s-eradicate-wild-horses-as-aliens is false. Equus caballus and Equus asinus left their DNA behind in the sediment in Alaska. Breeders recover DNA this way to use it to determine parentage of horses when the parentage is not known.
The fact that the modern horse evolved here during the middle or more recent Pleistocene explains the vast amount of genetic variation that is available to the species in order for it to survive. There were 16 different glacial and interglacial periods during the Pleistocene, and the horse had to develop the different genetic traits that allow the horse to survive in the arid desert as well as the cold, snow, and ice at the edge of the Arctic circle. For a so-called scientist to claim that the horse does not belong in any ecosystem on the continent where it adapted to live over millions of years and to have this same quasi-scientist continue to hold a position of influence over America’s scientific direction, research, what gets published where and how, is a travesty in a country that once sent a man to walk on the moon. This is not science. Science is a search for the truth; it is not about creating or covering up the truth.
LikeLike
AWESOME ABSOLUTELY AWESOME !!!!!
LikeLike
Here is an article from the Denver Post, about a dig near Snowmass Colorado, where they found evidence of horse fossils.
http://www.denverpost.com/news/ci_18274712
And this a youtube documentary, Ice Age Art – A Culture Show Special (4-5) about horses in prehistoric art – and man’s appreciation of the horse long before he realized it’s value.
What about this evidence don’t people understand?
LikeLike
While I havn’t yet read the article myself yet (working on getting it), this analysis by Beth Shapiro doesn’t invalidate the previous work on 10K old remains previously found in the Yukon in the 1990’s. According to Patricia Fazio, with whom i have discussed the 1990’s find at great length and on more than one occasion, the 10K find is definitely equis caballas, i.e., our modern horse. Until the qualified scientific community weighs in on how the recent research relates to this earlier information, its quite clear that it is too ealry to write our mustangs off as “feral”. Furthermore, bringing Przewalskis horse into it is a bit of a straw man argument anyway….since, according to Patricia Fazio who personally was part of this research and is in a position to know, today’s wild horses are only phenotypically different (not gentypically different) from the the 10K old yukon remains….this places the claim that przewalkis horse is only living primitive horse in dispute.
LikeLike