By Gege Li
A Himalayan red panda, which may be a separate species from its Chinese cousins
VPC Animals Photo/Alamy
We now have the strongest indicator yet that there are two separate species of red panda: the Chinese red panda (Ailurus styani) and the Himalayan red panda (Ailurus fulgens). Previously, these were classified as subspecies based on the pandas physical characteristics and location, but this has been contested due to a lack of genetic evidence.
To address this gap, Yibo Hu at the Chinese Academy of Sciences in Beijing, and his colleagues sequenced the whole genomes of 65 red pandas by extracting DNA from blood, muscle and skin samples taken from museum specimens and red pandas in captivity.
These red pandas came from wild populations living in the Himalayas in Nepal and India, or the Qionglai mountains in Chinas Sichuan province.
Using data from 49 red pandas, the team compared their haplotypes, variations in DNA inherited from a single parent for example, their mitochondrial DNA, which is inherited from the mother, and Y chromosomes, which are inherited from the father.
Compared to Chinese red pandas, the Himalayan red pandas had 50 per cent fewer mutations in the single letters, or bases, that make up DNA across their whole genomes . Hu’s team also found that the haplotypes clustered together in different regions of the genomes of Himalayan and Chinese red pandas, and there were no shared Y chromosome variants between red pandas from the eastern Himalayas and those from Sichuan.
Hu says this shows that they genetically diverged from each other, with minimal transfer of genetic variation between the populations, resulting in the two species. This divergence happened about 200,000 years ago, he says.
Physical differences between the two populations supported the classification the Chinese red panda has redder fur on its face and more prominent tail rings, for example.
Though there is clearly genetic differentiation between the sampled populations, no red pandas were sampled in Bhutan and northern India where the animals are also found, says Jon Slate at the University of Sheffield in the UK. Without having sampled pandas there, its harder to really confidently say there are two distinct species here, he says.
The genome analyses also showed that the Himalayan red panda underwent a drastic reduction in population three times, with the most recent decline taking place 90,000 years ago. This has resulted in a low genetic diversity and small population size in todays Himalayan species.
In comparison, the Chinese red panda experienced a population drop twice most likely due to glacial periods but managed to recover after each event.
However, both species numbers are dwindling due to habitat loss and climate change, though it isnt clear how many individuals are left in the wild. To conserve the genetic uniqueness of the two species, we should avoid their interbreeding in captivity, says Hu.
Journal reference: Science Advances, DOI: 10.1126/sciadv.aax5751
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By Gege Li