Original here http://www.3quarksdaily.com/3quarksdaily/2011/03/how-the-penis-lost...
HOW THE PENIS LOST ITS SPIKES
Zoë Corbyn in Nature:
Now researchers at Stanford University in California have found a molecular mechanism for how the human penis could have evolved to be so distinctly spine-free. They have pinpointed it as the loss of a particular chunk of non-coding DNA that influences the expression of the androgen receptor gene involved in hormone signalling.
"It is a small but fascinating part of a bigger picture about the evolution of human-specific traits," said Gill Bejerano, a developmental biologist at Stanford who led the work along with colleague David Kingsley. "We add a molecular perspective to a discussion that has been going on for several decades at least."
Published in Nature today1, the research also suggests a molecular mechanism for how we evolved bigger brains than chimpanzees and lost the small sensory whiskers that the apes — who are amongst our closest relatives and with whom it has been estimated we share 96% of our DNA — have on their face.