Oddly enough it seems much of what we are as human beings is not because of new developments as about giving away old ones.
This is what new research claims:
Cory Y. McLean et al., Human-specific loss of regulatory DNA and the evolution of human-specific traits. Nature 2011. Pay per view.
Discussed also at Science Daily.
|Will furry freaks find their way back to whiskers now?|
Some of these strategic deletions include the loss of a gene that forms the penile spine (John Hawks explains in detail what these spines are) of many other mammals. Similarly we lost the gene producing sensory whiskers. Both these losses are related to the androgen receptor gene (which we still have but whose function has been altered by loss of other related genes).
Many other key deletions have been detected in relation to steroid hormone signaling.
More interesting maybe is the loss of gene GADD45g, which limits brain growth. While the authors seem to agree that this deletion alone could not cause human large brain size and function, it does seem as it would be a central pillar of our brain development in any case.