Wild Iberian horses played part in horse domestication

January 8, 2010

A feral herd of modern Northern Iberian horses. © Carlos Puga

Workers dig at the Portalón archaeological site in the Sierra de Atapuerca (Spain). © Jaime Lira, Centro Mixto UCM-ISCIII


A modern lusitano. © US

Scientists have found evidence that wild horses from Iberia played a part in the domestication of the horse.
The earliest known domestic horses date to 4600 years ago. They originated on the steppes between modern Ukraine and Kazakhstan.

Two different hypotheses have been suggested:

That domestic horses spread from this area over the rest of Eurasia;
That horse domestication was a multiregional process, having occurred several times in different local places.
"Previous analysis on mitochondrial DNA from modern Iberian horses pointed to the D1 haplogroup as the most likely group involved in an independent domestication event, maybe in Iberia or in North Africa" explains Anders Götherström, from the Department of Evolutionary Biology at Uppsala University, who headed the project, together with Juan Luis Arsuaga of the Centro Mixto UCM-ISCIII from Madrid, Spain.
The researchers compared ancient DNA sequences from Iberian horse remains from the Neolithic, Bronze Age and Middle Ages obtained in this study with more than 1000 modern horse sequences from different Iberian and non-Iberian breeds, as well as with ancient sequences from other studies.

The researchers found the earliest occurrence of the D1 group in Iberia in a medieval horse. "We have not found sequences from the Neolithic or the Bronze Age period associated to the most important modern Iberian haplogroup, the D1 group," says Jaime Lira, of the Centro Mixto UCM-ISCIII from Madrid, and the main author of this study.

"That means that D1 group can be a foreigner group, which entered in Iberia during historical times."

The researchers unearthed evidence that wild horses from Iberia contributed to the domestication process, and the Lusitano group C is a witness from this event.

"The Lusitano C is a small group constituted only by modern horses from Iberian origin," explains Arsuaga.

"We have found that maternal lineages from this group were already present in wild Iberian horses from the Early Neolithic, continuing through the Bronze Age until nowadays."

These results suggest the possibility of a completely independent domestication episode, or the use of Iberian maternal lineages in a restocking process from the wild.

Collaborators on the research included scientists from Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos in Spain, Universidad Complutense de Madrid in Spain, Stockholm University in Sweden, Universitat Jaume I in Spain, Swedish University of Agricultural Sciences, University of Copenhagen in Denmark and Uppsala University in Sweden.

Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses Jaime Lira, Anna Linderholm, Carmen Olaria, Mikael Brandström Durling, M. Thomas P. Gilbert, Hans Ellegren, Eske Willerslev, Kerstin Lidén, Juan Luis Arsuaga and Anders G�therström