Debates around where domesticated horses came from has been a hot topic in the horse world for many years. For a long time, we believed that our modern equine friends originated from Przewalski’s horses, a rare and endangered ‘distant cousin’ subspecies native to central Asia’s steppes. However, a 2018 research publication by Science revealed compelling evidence of bridling, including bit marks on teeth remains of Botai horses, originally from a region North Kazakhstan, approximately 5500 ago. These findings suggest that Botai horses shared close proximity to humans long before Przewalski’s horses were around.
Surprisingly, DNA analysis and comparison with our modern horses revealed that Botai horses were not the ancestors of the domesticated horses that we know today, but instead, gave rise to Przewalski’s horses. This research was considered a breakthrough in our understanding that, what we once thought were the ancestors of our modern breeds, were actually feral horses descending from Botai horses’ lineage. Until today, the exact origins of modern domesticated horses remained unknown.
A breakthrough in research:
Excitingly, new research has shed a light on this mystery. Carbon dating and genetic sequencing technologies were used to compare the genomes of 273 ancient horse remains with our modern domestic horses. New peer-reviewed research led by Ludovic Orlando, a Professor in Molecular Archaeology at University of Toulouse, reveals that the modern domestic horses may have originated over 4200 years ago from the Western Eurasian steppes, specifically the lower Volga-Don region, known today as southern Russia.
The research points to a rapid expansion and breeding of this lineage around 2000 B.C, as they gradually replaced all other local horse populations across Eurasia. Evidence of the use of spoke-wheel chariots found in these regions also coincide with this timeline, suggesting that humans had started using horses for mobility and warfare shortly after the domestication of these horses.
Breaking down the genetics:
Researchers claim that specific behavioral and physical traits that were sought after in the domestication of horses can be traced back to the expression of two DNA sequences. Orlando points to the importance of the GSDMC and ZFPM1 genes, where “in humans, GSDMC is a strong marker for chronic back pain and lumbar spinal stenosis”, whereas the inactivation of the ZFPM1 gene in mice “causes anxiety disorders and contextual fear memory”. In breeding horses that expressed the desired phenotypes from these genes, our ancestors selectively bred for horses that showed higher docility, better temper, and stronger backs- allowing them to carry heavier weighs for longer distances.
Unbeknownst to them at the time, our ancestors were in fact carrying out what we know today as ‘genetic selection’ long before Darwin’s era!
While the latest findings pinpoint which lineage has successfully become our modern domestic horses today, it does not rule out that other forms of domestication may have been present before or in other geographical areas. While many questions are left to be investigated, this research provides an exciting piece of the puzzle in our understanding of how horses have impacted human migration in the early stages of civilization.