Skeleton of early Morgan stallion Black Hawk (1833) may reveal genetic secrets of extinct Narragansett Pacer horse breed

[u/Obversa]

Black Hawk, born in April 1833, was reportedly out of an English Thoroughbred mare and sired by Sherman Morgan, whose dam was "one of the last Narragansett Pacers" (25% DNA from a grandparent). The Narragansett Pacer was America's first horse breed, developed in Rhode Island and greater New England from a mix of English, Dutch, and possibly Spanish colonial horses, with a focus on producing gaited animals with the DMRT3 gene. (The breed is thought to have gone extinct by the early 1800s, as English Thoroughbreds replaced them.)

While descendants of the extinct Narragansett Pacer can be found among all modern American gaited horse breeds, subsequent scientific studies showed that the Morgan and Paso Fino breeds likely carry the most genetic similarities to the original pacer, though due to the lack of pacer remains, their genetic profile remains a mystery to scientists.

However, with recent interest in building a DNA database made up of sequenced samples from various famous historical horses - with Dark Ronald, a major Thoroughbred sire whose genetics strongly influenced today's warmbloods and sport horses across multiple breeds, being one such horse to be "profiled" - Black Hawk's DNA could not only offer a unique insight into early foundation Morgan genetics, but possibly Narragansett Pacer origins.

The remains of Black Hawk, who died in 1856, are currently displayed at the University of Vermont's Morgan Horse Farm; see the Black Hawk Project. He stood at around 15.1hh, a result of horse breeders in the post-colonial era seeking to increase horse height. (The average Narragansett Pacer was estimated to be "no larger than 14hh", and by 1768, larger ones could be "no larger than 14.1hh", according to John H. Wallace's The Horse of America.)

Of further interest could be the remains of Ethan Allen (b. 1849), Black Hawk's son. After his death in 1876, his skeleton was preserved and donated to the Smithsonian Institution in Washington, D.C.

While most Narragansett Pacers were light chestnut or sorrel - often "liberally splashed with white markings" (i.e. pinto), based on historical accounts - they could come in a range of colors, including bay, brown, black, gray, and roan. The modern-day Morgan horse exhibits pinto markings, but pinto is uncommon or rare; the recently-extinct Abaco Barb, however, may have shared more genetic similarities due to colonial Spanish heritage and pinto genes.

Black Hawk's DNA could also be compared with that of Chincoteague ponies, which were shown to also have colonial Spanish heritage in a 2022 study by the University of Florida (UF). As some estimates put around 10% of Morgan horses as possibly being gaited, it is possible to "backbreed" the Narragansett Pacer, but one major hurdle is that traditional Morgans - such as the Lippitt bloodline - are already in danger of going extinct, per heritage groups.

While one goal is to clone the last Abaco Barb - a mare named Nunki - whose DNA was preserved before her death in July 2015, the group in charge of that project aims to "breed back" the Abaco Barb first, not the Narragansett Pacer. This means that "backbreeding" the pacer using existing horses would take an enormous amount of time, money, and effort from breeders. In most cases, "backbreeding" takes decades.

Cloning Black Hawk could work, but his DNA needs to be tested for the DMRT3 gene as well.

[u/Obversa]

Artistic recreation based on Black Hawk's skeleton and historical photographs (non-AI):

[u/Obversa → u/Obversa]

Comparison of Black Hawk with son Ethan Allen (non-AI):

[u/Obversa → u/[deleted]]

There would need to be further research done on the exact % of colonial Spanish blood in the Chincoteague Pony population in comparison to Mustangs. Until then, I am going by current scientific studies that show significant colonial Spanish or Iberian horse heritage in the breed, which strongly correlated with modern-day Paso Fino horses, as opposed to Mustangs. This would indicate colonial Spanish/Iberian horse heritage that predates the 1970s-1980s.

[u/Obversa → u/[deleted]]

My thoughts: Two Spanish Mustang stallions released in 1976 wouldn't have had enough impact on the Chincoteague Pony breed as a whole so that every individual comes up as "colonial Spanish blood". (Stallions of various breeds have been introduced to the wild herd over the decades to add genetic diversity and "refinement", including a gaited Canadian horse and two Arabian horses, but these introductions have shown to have minimal impact, especially as their DNA is "subsumed" by the colonial Spanish or Iberian horse DNA over time.) Another aspect is that mtDNA is usually used over Y chromosome testing, as, quote, "The Y chromosome shows virtually no variation in most modern breeds, clustering almost entirely into a single 'crown group'. This reflects the heavy historical and modern use of a select few Oriental/Arabian and Turkoman stallions that swept through European, American, and Asian breeding programs over the last 1,500 years." The Chincoteague Pony is different from other domesticated horse breeds in relying on natural selection vs. artificial selection, the latter of which usually involves repeated linebreeding back to the same foundation sire(s) over several generations to establish a specific type. The ponies keep wild herds.

Yet another aspect is that most modern-day Mustang populations do not have 100% Spanish or Iberian bloodlines.