To investigate the history of domestic horses with respect to this charismatic phenotypic character, the scientists analysed a dataset of 201 samples of
ancient horse DNA.
Such is the case with an extensive new study of
ancient horse DNA, which largely disproves the current theory: that modern horses arose more than 5000 years ago in Kazakhstan.
Not exact matches
Their work on
ancient DNA from Viking Age
horses is more promising: Kool and Boessenkool have collected about 100 samples, in different states of preservation, from which they hope to build a detailed picture of how equine populations moved and changed.
It is the latest in a series of breakthroughs in
ancient DNA, coming just months after the sequencing of the oldest - ever genome, from a 700,000 - year - old
horse.
But the
ancient horses didn't have those mutations, indicating that those
DNA changes happened sometime within the last 2,300 years.
On a trip to collect
DNA samples from
ancient horse bones in Mongolia, Orlando got a whole new perspective on domestication.
But when Orlando and colleagues examined
DNA of
ancient horses, they found that the story started completely differently.
Through the Pegasus project, begun in 2015, Orlando and colleagues have collected
ancient DNA from
horse fossils from a wide variety of time periods and cultures.
The uninterrupted freeze of the permafrost preserved
DNA in the
horse bone, but since
DNA decays into smaller and less intelligible fragments over time, the specimen seemed too
ancient to analyze.
But in 2013, ultramodern
DNA extraction and sequencing techniques enabled researchers to access
ancient genetic codes and translate their evolutionary tales: Researchers in Denmark reconstructed a record - breaking 700,000 - year - old
horse genome, and geneticists in Germany began parsing the
DNA of 400,000 - year - old hominids.
Indeed, in a 2009 analysis of
DNA from the bones of nearly 90
ancient horses dated from about 12,000 to 1000 years ago, researchers found genetic evidence for bay and black coat colors but no sign of the spotted variety, suggesting that the spotted
horse could have been the figment of some artist's imagination.
Now, a new study of prehistoric
horse DNA concludes that spotted
horses did indeed roam
ancient Europe, suggesting that early artists may have been reproducing what they saw rather than creating imaginary creatures.
With this history in mind, paleogeneticist Ludovic Orlando at CNRS, the French national research agency in Toulouse, and the University of Copenhagen decided to analyze the
ancient DNA of these
horses.
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.
Ancient DNA reveals late survival of mammoth and
horse in interior Alaska Haile, J., D. G. Froese, R. D. E. MacPhee, R. G. Roberts et al. 2009.
Recovery of
ancient DNA, coupled with low - throughput gene candidate analyses, has previously been used to investigate changes in the genetic diversity of
horses over time.
In contrast, both the Dun and non-dun1 variants predate domestication, which is evident from the observation that
ancient DNA from a
horse that lived about 43,000 years ago, long before
horses were domesticated, carried both Dun and non-dun1 variants.
«This demonstrates that
horse domestication involved two different colour morphs (Dun and non-dun1) and future studies of
ancient DNA will be able to reveal the geographic distribution and the abundance of the two morphs», said Leif Andersson.
«While previous
DNA studies have produced evidence for bay and black
horses, our study has demonstrated that the leopard complex spotting phenotype was also already present in
ancient horses and was accurately depicted by their human contemporaries nearly 25,000 years ago.»