Do the little red-nosed reindeer and its ilk have a lot in common with the caribou of northern Quebec? More than one might think, suggests the work that an international team published earlier this year in the journal Evolution Letters. Indeed, despite centuries of domestication, the genome of domestic reindeer from Eurasia has remained surprisingly similar to that of wild caribou that live in Norway or northern Quebec.
Note that Eurasia is home to wild and domestic populations of reindeer, a northern deer known as caribou in North America. “The caribou and the reindeer, whether domestic or wild, belong to the same species, Rangifer fencing. On the other hand, around 3000 years ago, populations of nomads from Scandinavia domesticated this species to exploit its meat and skin. In addition, they have long used it to pull sleds and to transport loads,” recalls one of the signatories of the study, Steeve Côté, professor in the Department of Biology at Laval University, researcher at the Center northern studies and director of the Caribou Ungava program.
Have these few millennia of domestication left any traces? Very few, at least not on a global genome scale, demonstrate genomic comparisons carried out using samples taken from 9 wild caribou from Quebec and Norway and from 23 domestic reindeer from Norway, Siberia and China. Indeed, scientists found that there were few significant differences between wild and domestic caribou populations.
Furthermore, domestication does not seem to have had a major impact on genes associated with docility. “Rather, it is an inherent characteristic of the species and not the result of selective pressure for this trait. Wild caribou are not easily frightened by the presence of humans, unlike other deer such as white-tailed deer,” underlines Professor Côté.
The research team estimated the genomic gap that separates wild caribou from domestic reindeer using an indicator called the fixation index. She then compared it to what has been reported for other domestic species like dogs, cattle and sheep, which still have wild relatives. Result: this index is significantly lower for caribou than for other species.
“Unlike other domestic species, the reindeer has not been subjected to intense selective pressure nor to directed mating to select desirable traits,” emphasizes Steeve Côté. Domestic reindeer are kept in semi-freedom in large groups and they generally breed with the partner of their choice.”
— Steeve Côté, on the subject of the docility of reindeer
The research team estimated the genomic gap that separates wild caribou from domestic reindeer using an indicator called the fixation index. She then compared it to what has been reported for other domestic species such as dogs, cattle and sheep, which still have wild congeners, to discover that this index is significantly lower for caribou. than for other species.
“Unlike other domestic species, the reindeer has not been subjected to intense selective pressure nor to directed mating to select desirable traits,” emphasizes Steeve Côté. Domestic reindeer are kept in semi-freedom in large groups and they generally breed with the partner of their choice.”
Sami herders at work in a herd of reindeer.
— Michiel van Nimwegen
Despite the similarities between wild and domestic caribou populations, there are still genetic variations between caribou populations. Rangifer fencing coming from the different countries studied, continues the researcher. “They reflect adaptations to local conditions, such as those which distinguish the ecotypes of migratory, forest and mountain caribou in Quebec.”
Are domestic reindeer and wild caribou so similar that an individual could be easily transferred from one group to another? “A priori, it could work,” says Professor Côté. On the other hand, I don’t know how the domestic reindeer would find migrating several hundred kilometers! They’re the same species, but they’re not quite the same. There have been changes over several generations and the domestic reindeer therefore does not have a genotype as well adapted to the conditions experienced by the caribou. It is very likely that his chances of survival would decrease.”
