In 2015, Librado, et al, published "Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subartic environments." The mtdna research showed that Yakutians are related to Arabians, American Quarter horses, Monglians, Morgans, Norwegian Fjords, Standardbreds, Franches-Montagnes, and Icelandics.
But what was really interesting was the unique physiological adaptations that the breed made due to an extreme cold environment in a relatively short amount of time. Turkish speaking herders and riders brought their horses and cattle into Yakutia between the 13th and 15th centuries because of
pressure from the Mongol expansion.
pressure from the Mongol expansion.
Some of the adaptations documented in the Yakut breed--short and compact build, sensory perception of smell, fat accumulation, extreme hair density--are related to minimizing heat loss. Others are related to the endocrine/hormonal system for cold adaptation. Here is my best interpretation--adaptations to the liver that produce anti-freezing compounds, more adaptive regulation of the vasoconstriction/vasodilatation reflex following cold exposure, reduction of the volume of circulating blood, etc.
This research also helps explain why Siberian ponies (and some Icelandics and even Himalayan mules) were so valued during the early Polar expeditions. Some explorers thought the ponies were more useful than the dogs (although this did not prove out as a general conclusion) and became very attached to them. The attached pictures illustrate the Siberian "pony circus" of the Ziegler polar expedition, commanded by Anthony Fiala, from 1903 to 1904.
What is interesting is that some of these same changes were found among the Yakut human population and the wooly mamouth--great examples of convergent evolution. I wonder if I could blame my fat accumulation on a fictional Yakut ancestor. ;-)