A new study involving geneticists from Trinity College Dublin (TCD) has deciphered the prehistory of aurochs, the long-extinct animals which gave rise to domestic cattle.
Although the animals never reached Ireland, aurochs initially spread from Asia before roaming in Europe and Africa for hundreds of thousands, and in favouring similar ecosystems to humans, became intertwined with human culture and society.
As a result, the animal which was domesticated thousands of years ago, ultimately leading to today’s cattle, was the subject of some of the earliest human art.
The last wild auroch died in Poland in 1627, leaving most of their evolutionary history a mystery, according to TCD’s Dr Conor Rossi, the author of the study published in the scientific journal, Nature.
“However, through the sequencing of ancient DNA, we have gained detailed insight into the diversity that once thrived in the wild as well as enhanced our understanding of domestic cattle,” he said.
Gathering and analysing ancient DNA for over ten years, geneticists from TCD, together with an international team of researchers, discovered greater diversity among the animals than “ever imagined”.
Although European aurochs are usually considered one common form or type, the study suggests there were three distinct populations in Europe alone.
However, having analysed the DNA of cattle from 8,000 years ago, the study found that the domestication of aurochs in the Fertile Crescent more than 10,000 years ago resulted in a dramatic drop in this level of diversity.
Dan Bradley, Professor in Trinity’s School of Genetics and Microbiology, who led the study said the findings suggest nearly all of the cattle in the world today are descendants of just a “handful” of maternal auroch ancestors.
“This is something that only happened a couple of times, that isn’t necessarily something that was inevitable, it was some bit of human agency,” he said, adding that the domestication of aurochs would have been an “extraordinarily difficult” task due to animal’s size and nature.
“The nature of that domestication is of interest, it is one of the biggest achievements of humans,” he said, describing the animal as “iconic”.
Alongside insights into domestication, the study shows a response to a change in climate some 100,000 years ago.
The geneticists found that European and north Asian aurochs genomes separated and diverged at the beginning of the last ice age about 100,000 years ago, remaining apart until it ended when they began to mix again.
Genome-estimated population sizes dropped during the glacial period, with European herds losing the most diversity when they retreated to southern parts of the Continent before repopulating it again afterwards.
“Their history is dynamic with respect to climate and that’s interesting because they’re an animal that liked the same types of ecologies that we liked,” he said.
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