Researchers find no male protein in 23 Homo naledi teeth, raising female-only burial possibility

Researchers studying Homo naledi fossils from South Africa's Rising Star Cave system have found no trace of a male-specific protein in ancient tooth enamel, according to a study published in Cell. The team examined 23 teeth from at least 20 individuals in the Dinaledi Chamber and tested for Amelogenin-Y, a marker produced by a gene on the Y chromosome. The absence of that marker raises the possibility that the chamber held an exclusively female burial group, although the authors caution that other explanations remain possible.

The study used gentle acid etching to recover tiny peptide fragments from fossilized enamel, a method designed to preserve valuable specimens while extracting molecular information. Specialists at the University of York analyzed amino acid patterns to confirm the proteins were ancient rather than modern contamination. That validation matters because the central result is a negative finding: no Amelogenin-Y was detected. A missing marker can mean no males were present, but it can also mean the male-specific protein was absent because of mutation, gene loss, or preservation bias.

Homo naledi lived roughly 335,000 to 241,000 years ago and has puzzled researchers because adult fossils from Dinaledi show little variation expected between sexes. If the chamber was a female-only burial place, it would point to complex social behavior in a human relative other than Homo sapiens, including possible sex-based mortuary practices. The finding does not prove intentional burial, but it pushes scientists to consider demographic isolation, migration, or social selection as forces shaping who was placed in the cave and who survived to be studied.