Enamel proteins reveal biological sex and genetic variability in southern African <i>Paranthropus</i>

Abstract

<i>Paranthropus robustus</i> 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 ~2 million-year-old dental specimens attributed morphologically to <i>P. robustus</i> 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 <i>Paranthropus</i>. This study demonstrates how palaeoproteomics can help distinguish sexual dimorphism from other sources of variation in African Early Pleistocene hominins.