Newly released genomes provide insight into giant panda evolution

2021-03-02 Xinhua Editor:Li Yan

Chinese researchers have released the genomes of two giant panda subspecies, revealing the evolutionary characteristics of the giant panda.

Black-and-white giant pandas might all look similar, but there are two different types living in China, namely the Qinling and Sichuan subspecies.

The pandas from southwest China's Sichuan Province have bigger, longer heads and look more similar to bears. Those from the Qinling Mountains of the northwestern Shaanxi Province have rounder heads with shorter noses, meaning they look more like cats.

In a recent issue of Science Bulletin, researchers from Zhejiang University, the BGI Life Science Research Institution, the China Conservation and Research Center for the Giant Panda and other research institutes reported the genomes of the two giant panda subspecies, including the first genome assembly of the Qinling subspecies.

Compared with the first giant panda genome published in 2010, the quality of the two newly released genomes has been much improved with the development of sequencing technologies, said the researchers.

They found that giant pandas split into the Sichuan and Qinling subspecies about 10,000 to 12,000 years ago.

Genomic analyses showed that the loss of regulatory elements in the DACH2 gene and changes in the SYT6 gene may be responsible for the giant panda's low fertility rate.

The IQCD gene may be why Sichuan giant pandas have a relatively high fertility rate compared with the Qinling subspecies.

Fang Guosheng from Zhejiang University said that interaction between the two subspecies should be avoided in captive breeding programs. Hybrid offspring may have genetic defects, affecting the reproduction and survival of giant panda species.

In 2018, Shaanxi Province launched an ecological corridor program designed to connect the fragmented habitats of giant pandas to promote the gene flow between the wild population.

Fang noted that building ecological corridors will connect small groups of wild pandas in the Qinling Mountains and increase the stability of the Qinling subspecies' population. But the corridors should not connect the habitats of the two subspecies.

He said that the final step to protect giant pandas is reintroducing them into the wild. Based on genetic studies, breeding programs should ensure the fitness of giant panda offspring and strengthen them enough to adapt to living in the wild.

The number of giant pandas in captivity worldwide reached 633 in 2020. Fewer than 2,000 pandas live in the wild, mostly in the provinces of Sichuan and Shaanxi.

The Qinling Mountains are a major east-west mountain range in Shaanxi Province, providing a natural boundary between north and south China. Shaanxi Province borders Sichuan Province to the south. 

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