Chinese mountain cats swap DNA with domestic cats, but aren’t their ancestors

By | June 23, 2021

Wild Chinese mountain cats aren’t the ancestors of domestic cats, but the two types of felines still swap genes. The wildcats’ DNA is inscribed on the genes of some pet cats living on the Qinghai-Tibetan Plateau, but the mixing of genetic material extends back only a couple dozen generations, researchers report online June 23 in Science Advances.

Cats and humans have lived together in China for at least 5,300 years, yet previous genetic studies on feline domestication hadn’t included DNA from East Asian cats (SN: 12/17/13). So researchers wondered whether the mountain cats (Felis silvestris bieti or Felis bieti) had ever contributed to Chinese pets’ genes. Yes, the team found, but the short length of time mountain cats and housecats have been mating suggests Chinese domestic cats have their origins elsewhere, probably in the Middle East (SN: 6/19/17).

Shu-Jin Luo, a geneticist at Peking University in Beijing, and her colleagues came to that conclusion after they compared DNA from 27 Chinese mountain cats, 239 Chinese domestic cats and four Asiatic wildcats. The researchers didn’t encounter the elusive Chinese mountain cats in the wild; instead, they took samples from museum pelts, roadkill carcasses and zoo animals. The team did collect samples from the house cats, however. Rural Chinese cats come and go as they please, so “Oh, he’s not home yet, so we’ll wait for [an] hour” became a familiar refrain, Luo recalls.

Analysis showed that the pet cats’ DNA carried traces of mountain cat genetics up to 30 generations ago. The reason is “actually quite apparent, but nobody thought about it before,” Luo says. Domestic cats arrived on the Qinghai-Tibetan Plateau in the 1950s, most likely brought there by Han Chinese migrants. Census data show human population spikes in the region 70 years ago, coinciding with the earliest signs of hybridization of the wild and domestic cats, Luo says.

Most wild-domestic cat hybrids (one shown) have no outward signs of mountain cat genes lurking in their DNA. But subtle ear tufts hint at this pet’s wildcat heritage — and his DNA confirmed it.Meng Hao

Pet cats’ Y chromosomes hold clues about these encounters, carrying genes that can enter the gene pool only through mountain cat fathers. Male Chinese mountain cats seem to sneak into villages and mate with female housecats, not the other way around, Luo says. But her team isn’t just looking at the cats’ genetics to understand their history. In Scotland, the genetic distinctiveness of European wildcats has been nearly wiped out by breeding with feral cats. Luo and her colleagues suspected they might find similar effects in Chinese mountain cats.

The team didn’t detect domestic cats infiltrating mountain cat populations. But that doesn’t mean it isn’t happening. With more DNA samples, future work may reveal genes are already flowing both ways. “I’m not convinced that this is going in only one direction,” says Eva-Maria Geigl, a paleogeneticist at CNRS in Paris.

Modern interbreeding could threaten Chinese mountain cat conservation in the long run. Domestic cats’ genes could dilute or override traits that make mountain cats well adapted to high altitudes, Luo says.