Not all pandas are black and white: scientists have found out why some of them have a different color

Pandas with brown and white fur appeared as a result of natural variations, not inbreeding (crossing of closely related organisms) in conditions of population decline.

This was found out by scientists who studied the genetics of 11 individuals with this coat color living in the wild and in captivity. They are the results of their research published in the journal PNAS, writes CNN.

Large pandas with brown and white fur live on one mountain range in China.

The first brown panda known to science was a female named Dandan. A local ranger found her sick in Foping County in the Qinling Mountains of Shaanxi Province in March 1985. Panda was kept in captivity until her death in 2000.

“Repeated sightings of brown pandas suggest that this trait may be inherited. However, the genetic feature underlying the brown-white coloration of the fur remains unclear.” – write the authors of the study.

To understand its nature, researchers studied the male brown panda Kizai, who was rescued as a cub from Foping National Nature Reserve in Hangzhou in 2009. He is currently the only brown panda living in captivity.

Samples of his fur were compared under a microscope with those of three black and white pandas. The study found that Kizai’s brown fur had smaller melanosomes, the tiny cell structures responsible for skin and hair pigment in mammals.

What’s more, the research team found that this panda’s melanosomes were more likely to be irregularly shaped.

The researchers then collected genetic information about Kizai and compiled his family tree. Thanks to the fresh litter collected in the nature reserve, his mother – a black and white female panda Niuniu – was discovered. Scientists also identified the son of Kizai, a black and white panda born in captivity in 2020.

The scientists studied the genetic information from members of the Qizai family and compared it with the genetic information of 12 black and white pandas from the Qinling Mountains and 17 black and white pandas from other regions of China.

Although none of Kizai’s closest relatives had brown fur, the researchers were able to show that his parents and son had one copy of the recessive Bace2 trait, while Kizai had two.

By analyzing a tissue sample stored for more than two decades in ethanol, scientists were also able to sequence the genome of the first known brown panda, Dandan. They discovered that she had the same recessive trait.

The scientists then conducted a broader analysis of 192 black and white giant pandas. The mutation that caused the brown fur was only present in two pandas that come from the Qinling Mountains in Shaanxi, not Sichuan province, where most of China’s giant pandas live.

It is currently unclear what caused this genetic mutation.

“This may be due to the special environment of the Qinling Mountains, where the climate is different from that of Sichuan,” – says the senior author of the study, a professor of wildlife ecology and conservation biology at the Institute of Zoology, Chinese Academy of Sciences Fuwen Wei.

A better understanding of distinctive coloration may aid in the breeding of brown and white pandas in captivity. According to the International Union for Conservation of Nature’s Red List of Threatened Species, the giant panda’s species status is vulnerable.