Unlocking the Mysteries of Panda Coat Colors: A Genetic Revelation

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The giant panda is easily identifiable due to its striking coloration.

There are a few giant pandas that are not black-and-white, but instead have brown-and-white fur. These unique pandas can be found in a specific mountain range in China. Recently, scientists may have discovered the reason behind the rare pandas' unusual coats through new research.

Ami Vitale

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Pandas are making a comeback through research on their genetics. By studying pandas in the wild and in captivity, scientists have found that pandas with brown-and-white coats are not a result of inbreeding in a shrinking population, but rather a natural variation.

The first brown panda discovered by scientists was a female named Dandan. She was found by a local ranger in Foping County in Shaanxi province’s Qinling Mountains in March 1985. Dandan was kept in captivity until she passed away in 2000.

Since the finding of Dandan many years ago, there have been 11 reported sightings recorded through official news sources or personal stories shared with the authors of a recent study published in the journal PNAS on March 4.

The authors noted that the recurring instances of brown pandas suggest that this trait may be inheritable. However, the genetic basis behind the brown-and-white coat color is still unclear.

Senior author Dr. Fuwen Wei, a professor of wildlife ecology and conservation biology at the Chinese Academy of Sciences’ Institute of Zoology in Beijing, mentioned that understanding the unique coloration could help in breeding brown-and-white pandas in captivity. The giant panda is classified as a vulnerable species, according to the International Union for Conservation of Nature Red List of Threatened Species.

A wild giant panda in China's Qinling Mountains stares at the camera in March 2016.

A wild giant panda in China's Qinling Mountains stares at the camera in March 2016.

Xinhua/Shutterstock

A panda family tree

The researchers studied Qizai, a male brown panda rescued in 2009 from Foping National Nature Reserve in Hanzhong, to understand the trait. He is currently the only brown panda in captivity.

Qizai's brownish fur was compared under a microscope with hair samples from three black-and-white pandas. The researchers discovered that his fur had fewer and smaller melanosomes, tiny structures responsible for skin and hair pigment in mammals. Additionally, they found that the melanosomes in Qizai's fur were more likely to be irregularly shaped.

The researchers gathered genetic information about Qizai and traced his family tree. They found fresh scat, or bear poop, in the nature reserve which revealed the identity of his wild mother, a black-and-white female panda named Niuniu who wears a tracking collar.

In addition, the researchers discovered Qizai's son, a black-and-white panda born in captivity in 2020. By studying the genetics of a broader population of pandas, the study team later identified Qizai's father, Xiyue, a wild black-and-white panda that is tracked.

Courtesy Everland

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The scientists analyzed the genetic information of Qizai's family members and compared it with genetic data from 12 black-and-white pandas in the Qinling Mountains and 17 pandas from other regions in China, collected from scat and blood samples.

Even though none of Qizai's close family members had brown fur, the researchers discovered that his parents and son each carried one copy of the recessive trait on a gene called Bace2, while Qizai himself had two copies.

Some traits, like blue eyes or red hair, can be hidden in an individual's genes without showing up physically. Both parents need to have the same gene variant and pass it on for the trait to be seen in their child, just like with Qizai.

Genetic analysis helps to unravel mysteries and solve puzzles.

Thanks to studying a tissue sample kept in ethanol for over twenty years, scientists successfully sequenced the genome of Dandan, the first brown panda known. It was discovered that Dandan shared the same recessive trait as other pandas.

Further research was done on 192 black-and-white giant pandas to confirm that the gene responsible for the brown coats was Bace2. Interestingly, the mutation was only found in two pandas from the Qinling Mountains in Shaanxi, not in the Sichuan province where most of China's giant pandas are found.

A golden tiger spotted by wildlife photographer Gaurav Ramnarayanan in Kaziranga National Park in Assam, India, on January 24, 2024.

A golden tiger spotted by wildlife photographer Gaurav Ramnarayanan in Kaziranga National Park in Assam, India, on January 24, 2024.

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Conservationists are concerned about a rare 'golden' tiger that was recently photographed in India. Scientists conducted a study using the CRISPR-Cas9 gene-editing tool to confirm their findings. They identified a genetic sequence in the Bace2 gene that caused the mutation in 78 lab mice. By making a change, they were able to reduce the number and size of melanosomes in the mice.

Wei, the president at Jiangxi Agricultural University in Nanchang, China, mentioned that knockout mice have a light brown coat color.

He explained that this change in coat color suggests that the deletion has the ability to affect the pigmentation pathway in mice. Since this pathway is commonly shared among mammals, it is highly probable that this mutation could impact the coat color of a brown panda.

The genetic mutation was not caused by inbreeding, as previously thought. Wei believes it is more likely linked to the unique environment of the Qinling Mountains, which has a climate different from Sichuan.

"It is more likely that Qizai's unique coloration is due to natural variation rather than inbreeding. Our kinship analysis shows that Qizai's parents are not closely related," explained Wei.

Tiejun Wang, an associate professor at the University of Twente in the Netherlands, specializing in natural resources, mentioned that it was a positive outcome that Qizai's distinct coloration was not a result of inbreeding. Wang, who has researched brown pandas, was not part of the research team.

Wang, who worked as a field ranger in the mountains for 10 years, expressed his approval for the team's efforts in shedding light on this scientific question. He believes that this positive development will be reassuring for those who are concerned about this species.

Editor's P/S:

The discovery of the genetic basis behind the rare brown-and-white fur of certain giant pandas is a fascinating scientific breakthrough. It challenges previous assumptions about inbreeding and highlights the natural variations that can occur within a species due to environmental factors. The study underscores the importance of genetic research in understanding the evolution and diversity of wildlife.

The findings have significant implications for conservation efforts. By unraveling the genetic mysteries behind the brown-and-white pandas, scientists can gain valuable insights into their breeding behavior and develop strategies to protect and preserve this unique population. The research also opens up new avenues for exploring the genetic diversity of other endangered species and understanding the role of genetic variation in their survival. Qizai's family tree and identify the genetic mutation responsible for his coat color opens up possibilities for selective breeding in captivity. This could potentially help maintain the genetic diversity within the brown panda population and ensure the survival of this unique variation. Moreover, understanding the environmental factors that contribute to the mutation could provide insights into the role of habitat and climate in the evolution of animal species.