Did humans tame
themselves? One hypothesis put forward to explain humans’ high degree of
sociality and engagement in cooperation is the neural crest domestication
syndrome (NCDS), which states that traits associated with domestication are
linked to a reduction of neural crest cells during development. The author of
this review, A Molecular Investigation of
Human Self-Domestication, discusses the experiments done by Zanella et al.,
which uncover the potential link between domestication in humans and Williams-Beuren
syndrome (WBS), a disorder characterized by reduction of facial bone size and
hypersociality.
Individuals with
WBS have a 1.8Mb hemizygous deletion of 7q.ll.23, which includes the loss of BAZ1B, a gene that influences neural
crest cell migration and craniofacial development. Zanella et al. found that
when AMH genomes are compared to those of archaic hominins, including Denisovans
and Neanderthals, AMHs have fixed mutations in the BAZ1B gene that likely result in some loss of function. Presumably,
a decrease in BAZ1B expression would
lead to reduction in facial bone size, a trait that is observed in the more
gracile AMHs as well as other domesticated species. Taken together, these data
suggest that a reduction of BAZ1B expression
could have played a role in domestication and craniofacial phenotypes in AMHs.
Facial Phenotype Resulting from a
Reduction in BAZ1B Expression
Left
face shows craniofacial characteristics of AMH with WBS
Right
face shows craniofacial characteristics of typical AMH
Elaine Miller – Trends in Genetics Post 1
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