In 2013, a team led by Lee Berger discovered over 20 small-bodied hominin skeletons in the Rising Star Cave system of South Africa, dated to between 335,000 and 236,000 years ago. The species, Homo naledi, has sparked debate over whether the remains were deposited by accident or placed deliberately. Palesa Madupe and colleagues from the Max Planck Institute for Evolutionary Anthropology analyzed enamel proteins from 23 teeth representing at least 20 individuals, ranging from infants to older adults. They found only the female-specific protein AMELX, encoded on the X-chromosome, and no trace of the male-specific AMELY encoded on the Y-chromosome. Given the detection limits, the absence of AMELY indicates all individuals were biologically female.