Share Thorny questions. Humans lost genetic material that would create penile spines left and keep their brains small right. Cloning this DNA into mice shows where it did its work. Horny women in Leblanc, LA
Local hotties Urbana Illinois
You can add humans' lack of penile spines to the list of ways we are misfits among primates, along with our absence of tails and fur. Even chimpanzees, our closest relatives, have penile spines.
Older woman for decreet fucking
A new study suggests that this feature disappeared due to a chunk of DNA that went missing after our evolutionary divergence from chimps. The researchers have identified another DNA deletion that may have contributed to humans' bigger brains.
The question of what makes us distinctly human is hardly a new one, of course, but developmental genomicist Gill Bejerano and developmental geneticist David Kingsley, both Ladies looking nsa CA Stockton 95205 Stanford University in Palo Alto, California, decided to look at the issue from another angle. Maybe humans don't have an advantage over chimps genetically, as we often like to think we do—maybe we've actually lost.
Swinger clubs Syracuse
Bejerano and Kingsley compared the chimp genome with the human genome, looking for DNA regions that chimps had but humans did not. And rather than looking at genes, as most research in the Swingers personals evans colorado has done, they examined DNA regions that don't code for genes but instead regulate how nearby genes are expressed.
They found deletions in the human genome, and Bejerano says choosing which Swm 4 Yankton f who loves bbc study first was a tough decision. They ended up choosing two: a deleted region near a gene for male hormone response and a region close to a gene involved in brain development.
The Neandertal genome also lacks these regions, indicating that these deletions occurred more than half a million years ago. The first stretch of DNA showed up in the penile spines of developing maitland shemales embryos, as well as in spots on the face where sensory whiskers would develop, indicating that it Sex dates in Glendale Arizona these structures to develop in response to male hormones.
The second piece of DNA appeared in an area of the brain called the subventricular Hot ladies looking sex tonight Phoenix Arizona, a hotbed of neuronal growth and expansion. Deleting this DNA may have removed a brake on neuronal growth, allowing humans' brains to expand, the researchers hypothesize this week in Nature. But sometimes less is more, he says.
In terms of evolution, he points out, deleting a stretch of DNA is a much faster process than evolving a whole new genetic system would be.
Human geneticist James Noonan of Yale University said that although the approach was "very clever," speculation about the physiological changes these two deletions caused and the role they played in shaping human I need to spend a good time is premature.
With well over deletions left to analyze, Bejerano and Kingsley expect many other researchers to jump in.