Fig. 6. NFIX down-regulation is associated with modern human-derived traits.

a Vocal anatomy of chimpanzee and AMH. The vocal tract is the cavity from the lips to the larynx (marked by dashed lines). In AMHs, the flattening of the face together with the descent of the larynx led to approximately 1:1 proportions of the horizontal and vertical portions of the vocal tract. b Craniofacial features of the Neanderthal, healthy AMH, and AMH with Marshall-Smith or Malan syndromes. Each box shows a phenotype that occurs in the Marshall-Smith/Malan syndromes (i.e., when NFIX is partially or completely inactive). The righthand side of each box shows the observed phenotypes of individuals with the syndromes (left), healthy AMHs (middle) and Neanderthals (right). In most phenotypes, the observed phenotypes match the expected phenotypes based on NFIX expression. Binomial test P-value is shown.