For decades, the iconic Peking Man and his East Asian relatives have stood as silent witnesses to human evolution, their genetic secrets locked away inside precious, irreplaceable fossils.

Now, a Chinese-led team has coaxed ancient proteins from their teeth without causing damage — uncovering a direct molecular thread linking these early humans to a mysterious cousin and even to people alive today.

The study, published in Nature on May 13, was led by Fu Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences. Her team developed a micro-destructive acid-etching technique to recover enamel proteins from six Homo erectus teeth found at three sites in China: Zhoukoudian (the home of Peking Man), Hexian and Sunjiadong. The fossils date back at least 400,000 years.

Homo erectus was the first human species to venture out of Africa and occupies a pivotal branch of the human family tree. Yet until now, their molecular makeup had remained a frustrating blank because the fossils are fragile cultural treasures, traditional destructive sampling was simply not an option, stalling decades of research. The new micro-invasive method finally breaks that deadlock.

A concurrent commentary in Nature highlighted the significance of the find, noting that the enamel proteins provide “new insights into how ancient genetic material was eventually introduced into modern human populations”.

Beyond these evolutionary revelations, the study rolls out an entire toolkit for the future of minimally invasive fossil research.

“This work not only gives voice to Homo erectus at the molecular level for the first time, but also equips us to listen to many more ancient stories that were once thought to be lost,” the researchers wrote.