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Tiny DNA Tweaks Tied to Neanderthals’ Bigger Jaws, Study Finds

A Neanderthal enhancer drove stronger activation of the jaw-development gene SOX9 in embryo tests.

Overview

  • The peer-reviewed study, published November 10 in Development, was led by researchers at the University of Edinburgh’s MRC Human Genetics Unit.
  • Scientists pinpointed an approximately 3,000-base noncoding enhancer with three single-letter differences between Neanderthals and modern humans that regulates SOX9.
  • Dual-reporter assays in zebrafish embryos showed both human and Neanderthal enhancer versions active in jaw-forming progenitors, with the Neanderthal version more active.
  • Providing extra SOX9 enlarged the domain of jaw progenitor cells in the model, supporting a mechanism for more robust lower jaws.
  • The enhancer lies in a genomic region linked to Pierre Robin sequence in humans, and the team plans broader variant testing and in-dish facial development models.