The study, published in the journal Current Biology, focused on Y chromosomes, which are passed down from fathers to their male offspring. The findings show how heavily human-controlled breeding has shaped the modern horse.
Lead author Barbara Wallner, an animal scientist at the University of Veterinary Medicine in Vienna who specializes in evolutionary biology, explained that all such breeding is done to achieve specific goals. She said that some of these aims have been to produce horses that “run faster and with more endurance, perform better, and are healthy and beautiful. As breeds were formed, these goals were achieved faster by the introgression of foreign breeding studs.”
Wallner and her team could see the hybridization via their Y chromosome analysis of numerous horse breeds as well as related animals. They included a Connemara pony, South German draft horse, English thoroughbred, Warmblood Trakehner, Arabian, Icelandic horse, Lipizzan, Norwegian fjord horse, Shetland pony, Sorraia horse, Warmblood Oldenburg, Warmblood Swiss, Morgan horse, Standardbred, American Quarter Horse, Warmblood Baden Wurttemberg, Warmblood Holsteiner, Warmblood Hanoverian, Warmblood Bavarian, Warmblood Westphalian, French Montagne, Przewalski’s horse, and a donkey.
For the new study, the scientists overcame prior challenges by using deep, next-generation DNA sequencing. This allowed them to identify even the smallest changes to the 52 Y chromosomes included in the research.
Combining this chromosome data with written records, the scientists determined that, apart from a few Northern European haplotypes, all modern horse breeds included in the study clustered into a 700-year-old haplogroup. It mostly originated from the Original Arabian lineage of horses from the Arabian Peninsula and the Turkoman horse lineage from the steppes, or grasslands, of Central Asia.
“The purest descendant of the Turkoman horse today is the Akhal-Teke,” Wallner noted.
Horses are valued to this day, but because of their central roles in the societies of earlier times, they were prized more than almost anything else.
“By riding horses, humans were able to travel faster,” Wallner explained. “They could connect huge territories, and the domestication of the horse revolutionized warfare.”
Horse domestication goes back more than 5000 years, so the fact that most horses today descend from lineages dating to just 700 years ago shows how intense breeding from that time onward has greatly affected these majestic mammals.
A similar phenomenon has affected cats and dogs. Like horses, just a few key lineages are at the root of most breeding efforts. These animals, however, bred with local native species, creating the variety of types seen today.
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