NEW YORK – Domestic horses that arrived in the Americas alongside early Spanish colonialists in the late 1400s likely came from horse populations on the Iberian Peninsula, according to a new genetic analysis of a 16th century horse sample found in the north Haitian city of Puerto Real — an analysis that found similar horse ancestry in feral animals on an island off of the US East Coast.
"Historical scholarship on the sources of Spanish colonial horses suggests they were brought directly from Castile (central Spain) via the Canary Islands," first and corresponding author Nicolas Delsol, a postdoctoral researcher with the University of Florida's Florida Museum of Natural History, and his colleagues wrote, noting that "[p]revious DNA studies on modern breeds from the Americas also suggest a Spanish origin for early colonial horses."
After detecting domestic horse (Equus caballus) DNA in a tooth fragment originally analyzed as part of a colonial cattle study, investigators at the University of Florida and other centers put together a mitochondrial genome sequence for a horse representative linked to a settlement found in the present-day Puerto Real site until around 1600 — a mitochondrial sequence that was analyzed in combination with hundreds of published mitochondrial genomes for modern-day horses.
The team's findings, published in PLOS One on Wednesday, placed the Haitian horse in a Central Asian- and Southern European-centered mitochondrial cluster known as the equine haplogroup A.
"These results are consistent with an Iberian origin of this horse, as specimens of this haplogroup are found as early as the Bronze Age in the Iberian Peninsula," the authors reported. "This supports early colonial accounts that suggest Spanish Andalusia was the source of the first horses brought to the Caribbean."
Even so, the team explained, the ancient horse's genetic relationships were not limited to past horse populations, as it also showed genetic ties to a feral pony breed currently found on Virginia's Chincoteague Island.
"The origin of the Chincoteague ponies is popularized by a local oral history retold in the mid-20th century children's novel 'Misty of Chincoteague.' According to this story, Chincoteague ponies descend from a small herd of horses that escaped the shipwreck of a Spanish galleon during the colonial era," the authors explained, noting that "affinities between Caribbean horse breeds and the Chincoteague ponies may reflect Spanish efforts to colonize the Atlantic coast of North America."
Additional research into the genetics of present-day horse populations in that region, along with more intensive sampling and genomic analyses on ancient horse representatives, is expected to provide further details on the history of domestic horses and the processes that brought them to different parts of the world, the investigators explained.
They suggested that "[f]urther work on feral horse populations along the Atlantic coast of the United States, and continued horse archaeogenetic sampling promises to further clarify our understanding of how horses colonized the Western Hemisphere."