From: Centre National de la Recherche Scientifique [CNRS] in France, October 20, 2021 --
- The
modern horse was domesticated around 2200 years BCE in the northern
Caucasus.
- In
the centuries that followed it spread throughout Asia and Europe.
- To
achieve this result, an international team of 162 scientists collected,
sequenced and compared 273 genomes from ancient horses scattered across
Eurasia.
Horses were
first domesticated in the Pontic-Caspian steppes, northern Caucasus, before
conquering the rest of Eurasia within a few centuries. These are the results of
a study led by paleogeneticist Ludovic Orlando, CNRS, who headed an
international team including l’Université Toulouse III - Paul Sabatier, the CEA
and l’Université d’Évry. Answering a decades-old enigma, the study is published
in Nature on 20 October 2021.
By whom and where were modern horses
first domesticated? When did they conquer the rest of the world? And how did
they supplant the myriad of other types of horses that existed at that time?
This long-standing archaeological mystery finally comes to an end thanks to a
team of 162 scientists specialising in archaeology, palaeogenetics and
linguistics.
A few years ago, Ludovic Orlando's team
looked at the site of Botai, Central Asia, which had provided the oldest
archaeological evidence of domestic horses. The DNA results, however, were not
compliant: these 5500-year-old horses were not the ancestors of modern domestic
horses1.
Besides the steppes of Central Asia, all other presumed foci of domestication,
such as Anatolia, Siberia and the Iberian Peninsula, had turned out to be
false. The scientific team, therefore, decided to extend their study to the
whole of Eurasia by analysing the genomes of 273 horses that lived between
50,000 and 200 years BC. This information was sequenced at the Centre for
Anthropobiology and Genomics of Toulouse (CNRS/Université Toulouse III - Paul
Sabatier) and Genoscope2 (CNRS/CEA/Université
d’Évry) before being compared with the genomes of modern domestic horses.
This strategy paid off: although Eurasia
was once populated by genetically distinct horse populations, a dramatic change
had occurred between 2000 and 2200 BC. A genetic profile, previously confined
to the Pontic steppes (North Caucasus)3,
began to spread beyond its native region, replacing all the wild horse
populations from the Atlantic to Mongolia within a few centuries.
But how can this rapid population growth
be explained? Interestingly, scientists found two striking differences between
the genome of this horse and those of the populations it replaced: one is
linked to a more docile behaviour and the second indicates a stronger backbone.
The researchers suggest that these characteristics ensured the animals’ success
at a time when horse travel was becoming “global”.
The study also reveals that the horse
spread throughout Asia at the same time as spoke-wheeled chariots and
Indo-Iranian languages. However, the migrations of Indo-European populations,
from the steppes to Europe during the third millennium BC4 could
not have been based on the horse, as its domestication and diffusion came
later. This demonstrates the importance of incorporating the history of animals
when studying human migrations and encounters between cultures.
This study was directed by the the
Centre for Anthropobiology and Genomics of Toulouse (CNRS/ Université Toulouse
III – Paul Sabatier) with help from Genoscope (CNRS/CEA/Université d’Évry). The
French laboratories Archéologies et sciences de l'Antiquité (CNRS/Université
Paris 1 Panthéon Sorbonne/Université Paris Nanterre/Ministère de la Culture),
De la Préhistoire à l'actuel : culture, environnement et anthropologie
(CNRS/Université de Bordeaux/Ministère de la Culture) and Archéozoologie,
archéobotanique : sociétés, pratiques et environnements (CNRS/MNHN) also
contributed, as did 114 other research institutions throughout the world. The study
was primarily funded by the European Research Council (Pegasus project) and
France Genomique (Bucéphale project).
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