Chinese scientists have found proteins in teeth that are 400,000 years old. They studied tooth enamel from six people called Homo erectus. Homo erectus is an early human relative who lived in Africa and Asia a long time ago. The research shows a genetic link between Homo erectus and another early human group, the Denisovans. Proteins last longer in old fossils than DNA, so scientists can study them when DNA is missing.

The most important reason for this study is that proteins can sometimes survive in fossils when DNA cannot. The team compared the tooth proteins from the Chinese fossils with proteins from Denisovans, who also lived a long time ago in Asia. They found a similar genetic marker in both groups.

Because of this, scientists believe that Homo erectus and Denisovans may have met and had children together in Asia. This information helps scientists understand how early humans mixed and shared genes. The research was published in the science journal Nature in May 2026.