This image is a CT scan of a mouse's face — but not just any mouse. Scientists at Berkeley have identified thousands of small DNA regions responsible for influencing the development of facial features — and they used this insight to modify the faces of embryonic mice. The question now is, are humans next?
Top image: Harris Morrison, MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh.
Human faces are incredibly distinctive. But why? New research shows that our unique facial features are forged by more than 4,000 small regions of DNA — but it only takes a few genetic tweaks to subtly alter the shape of our faces.
It’s pretty obvious that facial features are hereditary. Just take a look at family resemblances. The shape of our faces are clearly influenced by our genetics, but scientists have only been able to isolate a small fraction of the genes responsible. Based on the complexity of our features, and those of other animals, it’s clear that there’s plenty more going on at the genetic level.
As Axel Visel of the Lawrence Berkeley National Laboratory in California and his colleagues have recently pointed out, there are thousands of specific non-coding regions of genomes that are working to influence the activity of facial genes. These short stretches of DNA act like switches, turning genes on or off.
These regions are called distant-acting enhancers, or transcriptional enhancers. Some scientists stupidly refer to them as “junk DNA” because they were initially thought to lack function, like encoding proteins. But despite the fact that these transcriptional enhancers are physically located hundreds of kilobases away from their target genes, they appear to regulate the spatial patterns, levels, and timing of gene expression in the normal development of facial features.