Pandas aren’t all black and white. Some come in a different shade, and scientists now understand why

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The giant panda is a well-known species thanks to its distinct coloring.

There are some giant pandas that have fur which isn't black and white. Instead, they have brown and white fur and can only be found in one mountain range in China. Scientists have recently discovered why these pandas have such a rare coat.

Researchers studied the genetic makeup of numerous wild and captive pandas and found that the brown-and-white coat color variant in pandas is not a result of inbreeding in a small population but rather a natural variation.

In March 1985, a female panda named Dandan was discovered by a ranger in Foping County in China's Shaanxi province's Qinling Mountains. It was the first time a brown panda had been scientifically recorded. Sadly, Dandan was kept captive until she passed away in 2000.

After Dandan was first discovered many years ago, there have been a total of 11 sightings that have been reported either in reliable news sources or through personal accounts shared with the researchers who published their study in the journal PNAS on March 4th.

The authors of the article stated that the frequent sightings of brown pandas suggest that this feature might be passed down through genetics. Nevertheless, the specific genes responsible for the brown-and-white fur color have not yet been determined.

Dr. Fuwen Wei, who works at the Chinese Academy of Sciences’ Institute of Zoology in Beijing, believes that studying the unique coloration of pandas could aid in breeding brown-and-white pandas in captivity. This could be crucial because the giant panda population is endangered, according to the International Union for Conservation of Nature Red List of Threatened Species.

The Panda Family Lineage

The scientists investigated the characteristic by examining Qizai, who is a young brown panda. He was saved from Foping National Nature Reserve in Hanzhong when he was very tiny back in 2009. Currently, he is the sole brown panda in confinement. The purpose was to discover the root of this feature.

After examining hair samples from three pandas with black and white fur, scientists used a microscope to compare Qizai's brownish fur. They discovered that his fur contained fewer and smaller melanosomes, which are tiny structures in cells responsible for hair and skin pigment in mammals. The research team also observed that Qizai's melanosomes were irregularly shaped.

Afterwards, the scientists collected Qizai's genetic data and reconstructed his genealogy. They identified his birth mother through recently deposited bear excrement found in the natural habitat. This female panda, referred to as Niuniu, is recognized by her black-and-white coloration and wearable GPS device.

Furthermore, the scientists discovered the offspring of Qizai, a newborn panda with black and white fur that was brought up in captivity last year. Subsequently, by examining the genetic profile of a larger group of pandas, the research team was able to identify Xiyue, a wild black-and-white panda that had been monitored.

Researchers examined the genetic data of Qizai's relatives and contrasted it against the genetic material of a dozen black-and-white pandas from the Qinling Mountains and seventeen black-and-white pandas from other areas in China, utilizing dung and blood examples.

Even though none of Qizai's close relatives had a brown coat, scientists discovered that both his parents and son carried one version of a less dominant feature on a gene called Bace2, while Qizai possessed two versions.

A person's genetic makeup can contain hidden traits, like having blue eyes or red hair, that aren't visible outwardly. With certain traits, both parents need to have a copy of the gene and pass it down for the trait to manifest in their child. This is what happened with Qizai.

The scientists made an exciting discovery by examining a preserved tissue sample that had been stored in ethanol for over 20 years. They were able to decode the entire genetic makeup of Dandan, who happens to be the original brown panda. The team of researchers discovered that Dandan carried the same rare genetic feature as other brown pandas.

Afterward, the researchers carried out a more extensive investigation on 192 giant pandas with black and white fur to confirm that the Bace2 gene was responsible. The alteration that led to their brown fur was only detected in a pair of pandas that came from the Qinling Mountains in Shaanxi, not in Sichuan province where the majority of China's giant pandas reside.

The researchers verified their results by utilizing the CRISPR-Cas9 gene-editing technique to eliminate the specific genetic code they had pinpointed as the culprit for the Bace2 gene mutation in 78 laboratory mice. This alteration resulted in a decrease in the amount and dimension of the melanin-containing organelles in the mice.

According to Wei, who currently holds the position of President at Jiangxi Agricultural University in Nanchang, China, the knockout mice display a light brown coat color.

This indicates that getting rid of this particular gene can potentially change the mouse's coat color. Since the pigmentation process is similar across mammals, there's a high chance that this mutation can also affect a brown panda's fur color.

The reason for the genetic mutation is uncertain. Wei believes it may be related to the unique environment of the Qinling Mountains, which has a distinct climate from Sichuan. They have ruled out inbreeding as a possible cause, which was previously suspected.

Wei stated that Qizai's unique fur color is probably due to natural differences rather than breeding within the same family. According to our analysis of kinship, it appears that Qizai's parents were not closely related.

Tiejun Wang is an associate professor who specializes in natural resources at the University of Twente in the Netherlands. He mentioned that it's great to hear that the exceptional fur color of pandas is not due to a lack of variation in their breeding. Wang has researched brown pandas in the past, but he wasn't a participant in this particular study.

Wang, who spent 10 years working as a field ranger in the mountains, expressed optimism about the recent progress made in protecting this particular species, which should reassure those who are invested in their conservation.

According to Wang, he appreciates the team's remarkable endeavors in attempting to uncover the answer to this scientific inquiry.