Equus was domesticated twice, 5500 years ago and 2200 years ago !

As part of this study, the research team assembled a vast collection of archaeological horse remains covering the whole of Eurasia. Using state-of-the-art techniques for sequencing ancient DNA, the scientists were able to analyze with unprecedented precision the genetic transformations that accompanied the emergence of domestication, breeding and the use of horses for transport.  

First, they sought to pinpoint when the ancestors of today's domesticated horses first left their original home in the Don Valley. Next, they reconstructed the horses' demographic history to identify when breeders began to produce them on a large scale. Finally, they looked for clear genetic signs of deliberate manipulation of animal reproduction by early breeders.

These three clues (date of the start of the domestic horse boom; demographics; breeding manipulation) all depict a coherent story where domestic horses were produced in sufficient numbers to meet an exponential demand across the continent, starting just 4,200 years ago. Consequently, this date, and no other before it, marks the beginning of a new era in human history in which horse-based mobility emerged to remain a central feature of our societies until the rise of combustion engines from the late 19th century onwards.

Research into ancient DNA preserved in human remains had previously revealed that the human genetic landscape of Europe had undergone a radical change following the migration of peoples from the steppes around 3000 BC, often described as horsemen and speakers of a proto-Indo-European language. New research and precise dating show no sign of such upheavals among horses of the same period. So, despite the omnipresence of horse-related vocabulary in Indo-European languages, humans did not use horses as a means of transport during these early migrations, since the domestication and subsequent spread of the Equus caballus horse began 2200 years BC. 

The work published today describes a particularly innovative method for establishing that horse generations began to pass much more quickly at the very moment when their production became massive and they invaded the continent. The reason why the first breeders were suddenly able to produce such colossal numbers of horses to meet a demand that had become widespread was that they were able to raise and breed younger and younger horses, almost doubling their production capacity.

The research team found the same signs of a considerable acceleration in the rate of generations within a lineage distinct from that leading to modern domestic horses. This lineage was discovered at Botai, a site in Central Asia where horse pens and signs of milking and harnessing have been described, but remain hotly debated. The new genetic index unveiled by the study argues in favour of advanced control of horse breeding by breeders. It supports interpretations that the sedentary Borotai people succeeded in domesticating another horse lineage 5,500 years ago to exploit its meat and milk. This Botaï line subsequently became extinct. So the Equus horse was indeed domesticated twice: first to eat it (Botaï horse), and long afterwards to ride it (Equus caballus).

The BIGE team, in partnership with the Musée Fragonard at ENV d'Alfort, has contributed to studies on the origins of horse domestication and the diversity of modern horse breeds, notably with access to rare samples of ancient DNA from 18th and 19th century horses, and of course to modern breeds whose genomes have been sequenced. Since 2015, this collaboration has enabled us to learn more about the origins of modern European breeds, the segregation of favorable and unfavorable mutations over the course of evolution, and to develop original molecular and quantitative genetic methods such as imputation.

Contact 

• Contact CNRS : Simon Leveque, Ludovic Orlando 
• Contact scientifique UMR GABI : Eric Barrey 

Reference :
Librado, P., Tressières, G., Chauvey, L. et al. Widespread horse-based mobility arose around 2,200 BCE in Eurasia. Nature (2024). https://doi.org/10.1038/s41586-024-07597-5