Sequenced Reindeer Genome Reveals Common Ancestry With Cattle, Goat

Reindeer are widely known for being Santa’s sled pullers. They hold a special place in every Christmas celebration and rendition of ‘Rudolph the red-nosed reindeer.’ Reindeer or caribou (as known in North America), which are native to arctic, subarctic, tundra, boreal and mountainous regions of northern Europe, Siberia and North America, are the latest animals to get their genome referenced and enter the growing list of domesticated species.

Reindeer or Rangifer tarandus have many unique characteristics. Unlike other cervids, female and male reindeer regularly grow antlers. Their milk contains more protein and less lactose compared to that of cow. This could be beneficial to humans given the rise of lactose intolerance among people.

“With this variety of unique features, the availability of a reindeer genome sequence can provide an entire sleigh-full of new information, and is a welcome new member to the elite club of domesticated species with reference genomes, including the cow, sheep and goat,” the researchers from China said in a Sci-News.com report .

The study of the blood sample from a two-year-old female reindeer of a domesticated herd maintained by nomadic Ewenki hunter-herders in the Greater Khingan Mountains in China led researchers to understand in detail the evolutionary history of the animal. The set of available genes and genome collected from the reindeer were used to construct an evolutionary tree of the bovine family. Researchers sequenced, assembled, annotated the genome, which was 2.6 GB (2.6 billion base pairs) in size, which is slightly smaller than those of humans, cows and goats and about the same size as sheep, the report added.

The team successfully concluded reindeer, cattle and goats separated from a common ancestor approximately 29.6 million years ago, said the study published in journal GigaScience. This research provided scientists with a greater understanding of the deer species, which have not been domesticated yet and herbivore mammals in general.

“We also identified 335 reindeer-specific genes that are likely to aid in understanding the special biological characteristics of reindeer,” said first author Dr. Zheping Li, from the Institute of Special Animal and Plant Sciences at the Chinese Academy of Agricultural Sciences. “These could also be very useful in understanding the evolution of the reindeer as well as all Cervidae in future comparative genomics studies between reindeer and other ruminants.”

The team also traced the common ancestry back to a period called Oligocene epoch, which was almost 30 million years ago.

“This was during the Oligocene epoch, when one of the major changes was the global expansion in grasslands,” the researchers said.

The fact that a split in herbivore species happened with the expansion in grasslands throws light on several aspects of the existing models of evolution. According to the team, the research will help scientists understand the animals better and create an improved, more complete model of evolution.