Geneticists unlock ancient tales of cattle herding and evolution
Posted on: 11 July 2019
Livestock herding began in the ancient Near East and underpinned the emergence of complex economies and then cities. Subsequently, it is in this region that the world’s first empires rose and fell.
Now, ancient DNA extracted from ancient bones has revealed how the prehistory of the region’s largest domestic animal, the cow, connects with these events.
Geneticists from Trinity, together with an international team of archaeo-zoologists, have deciphered the history of early bovines by sequencing 67 ancient genomes from both wild and domestic cattle sampled from across eight millennia.
“This allowed us to look directly into the past and observe genomic changes occurring in time and space, without having to rely on modern cattle genetic variation to infer past population events,” said Postdoctoral Researcher from Trinity, Marta Verdugo, who is first author of the article published today in leading international journal, Science.
Sequencing Near Eastern wild cattle, or aurochs, allowed the team to unravel the domestication process of this most formidable of beasts. Whereas their genetic similarity to the early domestic cattle of Anatolia concurs with a primary origin in that region, it is clear that different local wild populations also made significant additional genetic contributions to herds in Southeast Europe and also in the southern Levant, adding to the distinctive make up of both European and African catlle populations today.
These earliest domestic cattle are Bos taurus, with no ancestry from Bos indicus, or zebu – herds that originate separately further to the east in the Indus Valley.
“However, a dramatic change occurred around 4,000 years ago when we detect a widespread, wholesale influx of zebu genetics from the east,” added Dr Verdugo.
The rapid incursion that occurred at this point may be linked to a dramatic multi-century drought that was experienced across the greater Near East, referred to as the 4.2 kya climate event.
At this time the world’s first empires in Mesopotamia and Egypt collapsed and breeding with arid-adapted zebu bulls may have been a response to changing climate by ancient herders.
Professor of Population Genetics at Trinity, Dan Bradley, said:
This was the beginning of the great zebu diaspora that continues to the present day – descendants of ancient Indus Valley cattle are herded in each continental tropics today.
There is a great power in ancient genomics to uncover new, unforeseen tales from our ancient history.
This research was funded by a European Research Council Advanced Grant to Professor Dan Bradley.