Enamel proteins reveal biological sex and genetic variability in southern African Paranthropus

Paranthropus robustus is a morphologically well-documented Early Pleistocene hominin species from southern Africa with no genetic evidence reported so far. In this work, we describe the mass spectrometric sequencing of enamel peptides from four similar to 2 million-year-old dental specimens attributed morphologically to P. robustus from the site of Swartkrans in South Africa. The identification of AMELY-specific peptides enabled us to assign two specimens to male individuals, whereas semiquantitative mass spectrometric data analysis attributed the other two to females. A single amino acid polymorphism and the enamel-dentine junction shape variation indicated potential subgroups present within southern African Paranthropus. This study demonstrates how palaeoproteomics can help distinguish sexual dimorphism from other sources of variation in African Early Pleistocene hominins.