Alpine marmots have survived the ice age and exquisitely adapted to cold climates. However, these furry animals were found to be the least genomically-diverse species.
A study by a team of international researchers from the Charité Institute of Biochemistry in Berlin on the alpine marmot's genome reveals that these animals lost their diversity during the historic ice age climate events, making them very similar in terms of genetic makeup. The scientists originally targeted to probe the alpine marmot's lipid metabolism but their unexpected discovery showed how climate change can affect the genetic diversity and variation of a species.
Role Of Climate Change In Loss Of Genetic Diversity
Alpine marmots are large rodents belonging to the squirrel family. They have plump and sturdy bodies, with their body mass changing drastically from one season to another. Their fur color also ranges from a combination of blond, reddish, and dark gray.
They dwell beyond the tree lines in high-altitude mountain areas wherein they burrow and hibernate underground for several months in a year. Their estimated population size is still over 100,000 and they are not considered to be at risk of extinction. They have a long lifespan of about 15 to 18 years.
The research found evidence suggesting that the marmot's adaptation to colder temperatures during the climate shifts of the Pleistocene steppe resulted in longer generation time, and a decrease in the rate of genetic mutations. As a result, these animals were unable to successfully regenerate their genetic diversity despite their large population.
Even the scientists were astonished to discover that the alpine marmots are the least diverse of all the wild animal species ever studied.
"We would not have expected the genetic diversity of alpine marmots to be so low," said Toni Gossmann, first author of the paper and researcher at the University of Sheffield and Bielefeld University in Germany.
The study argues that the case of the Alpine marmot highlights the complicated relationship between climate change, genetic diversity, and conservation status.
"It shows that species of extremely low genetic diversity can be very successful and persist over thousands of years, but also that climate-adapted life history can trap a species in a persistent state of low genetic diversity," the researchers stated in their study.
Bottleneck Effect Resulting From Adaptations
For the study, the scientists used computer-based analysis to reconstruct the marmots' genetic past and compared the resulting analysis with fossil data. Apparently, the marmots underwent two adaptations: during the animal's colonization of the Pleistocene steppe at the beginning of the last ice age or between 110,000 and 115,000 years ago and .when the Pleistocene steppe disappeared again toward the end of the ice age or between 10,000 and 15,000 years ago.
When the ice age ended, the animals were forced to retreat to the high Alps to avoid the warming climate. This led to a "bottleneck effect," which the marmots were not able to recover from since the Pleistocene steppe.
The researchers will also investigate other animals that survived the ice age to know if there are other species trapped in a state of low genetic diversity.
The study is published in the journal Current Biology.