Proteins in the teeth of Homo erectus show that the Denisovans gave us their DNA

Human ancestry has come to be better understood thanks to our ability to find ancient DNA. We now know that, when humans left Africa, they joined the groups they met there, the Neanderthals and the Denisovans. Evidence from the Denisovan genome also suggests that this was not new; the Denisovans had apparently interbred with a much earlier group. But it is not yet known who the group is.

Now, some evidence from ancient proteins suggests that the secret group was The man stood upspecies that left Africa more than a million years ago and spread to Eurasia. And, thanks to the Denisovans, it seems that modern humans inherited some of it The man stood up DNA.

In the teeth

Without access to all the repair enzymes produced by living cells, DNA is rapidly damaged. The two pieces of the helix, and the base change identity or collapse completely. Although the cold and dry environment reduces this, it puts a limit on how far we can find DNA. So far, it seems The man stood up it remains on the far side of that time limit.

To overcome these limitations, people have turned to proteins. Although these also break down over time, there are few structures, such as bone and teeth, that are strong and protect proteins from the environment. By studying the proteins in tooth enamel, for example, researchers have found he got the schedule amino acids from protein fragments that are 2 million years old.

Given the success in the past, a group of Chinese researchers decided to use small samples of The man stood up teeth from three sites in China, each about 400,000 years old. He started by taking samples from animals at the same site and proved that he was able to isolate and identify protein fragments from tooth enamel. Once they were confident in their performance, the researchers turned to five The man stood up samples are cast in a Denisovans from Harbin also.

According to six The man stood up People who looked at them, found pieces of six to 11 enamel proteins. The Harbin man gave a similar figure, and a few previous studies found data from people elsewhere, including a Denisovan from near Taiwan and an ancient man from Spain.