A bioinformatics analysis of RUNX2 (A transcription factor essential for osseous morphogenesis and metopic suture closure regulation) with possible implications for hominin brain evolution

Recent sequencing of the Neanderthal genome reveals signs of positive selection in the modern human variant of the RUNX2 (CBFA1) gene, which is known to affect metopic suture fusion, as well as being essential for osteoblast development and proper bone formation. It is possible that evolutionary changes in RUNX2, affecting aspects of the morphology of the upper body and cranium, were of importance in the origins of modern humans. To contribute to a better understanding of the molecular evolution of this gene, probably implicated in human evolution, we performed a comparative bioinformatic analysis of the coding and coded sequences of RUNX2 in Homo sapiens, Pan troglodytes, Gorilla gorilla, Pongo abelii, and Macaca mulatta. We found differences between Homo sapiens and the other Primates examined in amino-acid sequences of certain RUNX2 protein isoforms, which may have important implications for the timing of metopic suture closure. However, further studies are required to clarify the potentially distinct developmental roles of different species-specific N-terminal isoforms. Future studies may be particularly important for gaining a better understanding of possible evolutionary changes in the molecular mechanisms underlying the likely modification of frontal neurocranial ossification patterns that occurred during hominin brain evolution.