A monk's discovery
In 1980, a Buddhist monk meditating in Baishiya Karst Cave, a sacred site high on the Tibetan Plateau, found a human jawbone. Recognizing its potential importance, he gave it to a local religious leader, who then passed it to Lanzhou University. For decades, the fossil remained an enigma. Its robust, primitive shape and large molars were unlike modern humans, but its identity was unclear. The jawbone sat unclassified until a new generation of scientific techniques could finally reveal its identity. The cave itself is located at an altitude of 3,280 meters (10,760 feet), an environment with dangerously low oxygen levels for most people.
The protein puzzle
The fossil's high altitude and great age made extracting DNA impossible. Instead, scientists turned to a newer method: paleoproteomics. They drilled into the dentin of one of the molars and managed to extract fragments of ancient, degraded proteins. By sequencing these proteins, they could reconstruct their genetic code. The analysis, published in 2019, showed matched the Denisovans, a mysterious group of archaic humans previously known only from a few tiny bone fragments and teeth found in Denisova Cave in Siberia, over 2,200 kilometers away. This was the first time an ancient hominin was identified using protein analysis alone.