Scientists from the University of Singapore have found that jungle hens are threatened with extinction by mating with domestic chickens, PLOS Genetics reported.

Today, there are five wild subspecies of chickens that are the ancestors of domestic chickens. All of these subspecies can successfully breed with domestic chickens, which means that chicken genes that have been artificially selected by farmers can be introduced into wild populations.

Scientists have sequenced the genomes of more than a hundred domestic and wild chickens, both modern and those that lived a century ago. The results showed that 20 percent to 50 percent of the genes of wild jungle chickens were inherited from domestic chickens, and the rate of genetic mixing increased over time.

Despite this mixing, subspecies are still separate because they have not received genes that play a key role in domestication. But if mating between wild and domestic chickens continues, wild chickens may be on the verge of survival, as they will not be able to adapt to the changing environment because of the domestic genes.

In doing so, chicken breeding will also suffer, as researchers can now use wild subspecies as a genetic reservoir to find new genes that make an animal more resistant to a certain disease, for example.