Protein analysis of 23 fossil teeth shows every Homo naledi individual recovered from the Rising Star cave system was biologically female, researchers reported.
An international team extracted ancient proteins from teeth found in the Rising Star cave system at the Cradle of Humankind World Heritage Site. No trace of the male-specific Amelogenin-Y protein appeared in any sample.
The study, published in the journal Cell, was led by researchers from the University of Copenhagen and the University of the Witwatersrand. Co-author Professor John Hawks said the team examined teeth from all known individuals in the system.
Professor Lee Berger noted the statistical improbability of sampling only one sex by chance. The findings suggest possible sex-specific mortuary practices among this extinct hominin species that lived between 335,000 and 241,000 years ago.
Lead author Dr Palesa Madupe said the method used was minimally invasive and preserved the fossils. Researchers cautioned that a genetic mutation cannot yet be ruled out as an alternative explanation.