Humans and dogs evolved together

Dogs are not only the closest human beings but they are also our companions in evolution.

No one knows exactly when humans began to tame wolves. Scientists once found a dog skull in Russia's Siberia Mountains. Chronology of the skull shows that humans began to tame gray wolves from 33,000 years ago. But some studies show that domesticated dogs are only about 16,000 years ago.

Some previous studies prove that wild dogs in southern China were the first domestic dogs.

Artwork: demotix.com.

To find out the process of domesticated dogs in southern China, Guo-dong Wang, a genetic researcher of the Chinese Academy of Sciences, and colleagues analyzed the DNA of four gray wolves and three children. Native dogs in China, a German shepherd dog, a Belgian Malinois and a Tibetan clam dog.

Results of DNA analysis showed that gray wolves separated from Chinese native dogs from about 32,000 years ago, Livescience reported.

'It is possible that indigenous Chinese dogs are the missing link in the process of domesticated dogs into domestic dogs,' the team said.

The team compared genes that govern digestion and metabolism. They found mutations in the genes of both species. For example, mutations occur in genes that control the transport of cholesterol.

They also found the phenomenon of 'parallel evolution' in many processes in the human brain and dogs. For example, the genes that control the processing of serotonin - a chemical in the brain - of two species change. In humans, different variants of this gene affect the level of anger.

The finding shows that wolf domestication has taken place much earlier than the hypotheses that scientists have made. It also shows that dogs and people evolved from tens of thousands of years ago in the same environment.

'The process of domesticated wolf takes place in the context of increasing population density and living space becomes more narrow. Those adverse environmental factors can become evolutionary pressure for both species , 'the team argues.