In the latest episode of the Genetics Unzipped podcast, Dr Kat Arney takes a look at the monkey in the mirror, investigating how flipped genetic switches and long-dead viruses make all the difference between our human faces and those of our closest primate relatives.
What makes a face?
Kat takes a closer look at research from Professor Joanna Wysocka from Stanford University, who’s studying how our genes build our bodies, particularly the highly unique and recognisable features of our faces.It all starts with the neural crest – a small transient population of migratory cells with multiple roles in embryogenesis, including building the structures of the vertebrate face.
Very simple fish called lancelets, thought to be similar to the kinds of creatures that were around hundreds of millions of years ago – don’t have a face as we’d recognise it. Instead, their long body ends in a nubby bump and a few waving tentacles. They also don’t have proper neural crest cells as far as anyone can tell. Neither do lampreys, whose long body ends in layers of rasping teeth round a gaping circular mouth. No neural crest, no face.
The monkey in the mirror
To find out more about how our faces are made, Wysocka and her team have been comparing the genetic differences between neural crest cells from humans and those from our nearest relatives, chimps, by using induced pluripotent stem cells grown in the lab.
They’ve found that although the genes are very similar between the two species, there are key differences in the activity of the genetic switches (known as enhancers) that turn them on. Curiously, many of these enhancers seem to be derived from long-dead retroviruses that inserted themselves into the human genome many millennia ago.
Could it be these viruses that made us human?
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Genetics Unzipped is the podcast from the UK Genetics Society, presented by award-winning science communicator Dr Kat Arney and produced by First Create the Media. Follow Genetics Unzipped on Twitter @geneticsunzip, and the Genetics Society at @GenSocUK