Post from RedOrbit Staff & Wire Reports via Pandas International
By re-sequencing the genomes of nearly three dozen wild giant pandas, a team of Chinese scientists say that they have managed to construct a complete, continuous history of this rarest member of the bear family, from its origins to the current day.
The researchers, who were led by the Institute of Zoology at the Chinese Academy of Sciences (CAS) and the genome sequencing center BGI, completed whole genome re-sequencing of 34 members of the species. They discovered that the six modern-day geographic giant panda populations could be divided into three genetic populations: Qinling (QIN), Minshan (MIN), and Qionglai-Daxiangling-Xiaoxiangling-Liangshan (QXL).
“We have identified three genetic populations of giant panda for the current six geographic populations lived in western of China,” Shancen Zhao, Project Manager from BGI, said in a statement on Sunday. Those three populations emerged after the giant pandas were impacted by several key evolutionary events over the years, including a pair of population expansions, two bottlenecks, and two population divergences, the researchers explained.
While the pandas we know today thrive on a diet of bamboo, their ancestors were omnivores or carnivores, with bamboo becoming the primary source of culinary sustenance for the creatures about three million years ago. It was then that the giant panda experienced its first population explosion, thanks largely to the warm and wet weather conditions that made bamboo more and more prevalent, the researchers said.
About 700,000 years ago, the population experienced a decline due to two Pleistocene glaciations in China. Following the retreat of those glaciations, the second population explosion occurred, with the bear species reaching their peak population between 30,000 to 50,000 years ago, the scientists explained.
More recently, the giant panda split into Qinling and non-Qinling populations about 300,000 years ago, and the non-Qinling split into the MIN and QXL populations approximately 2,800 years ago.
“They also found the evidence that population fluctuations were driven by global climate shifts, but recent human activities have likely caused population divergence and the serious recent decline.”