One gene helped human brains become complex

Two extra copies of the SRGAP2 gene appear to have led to slower human brain development, but denser interconnection between neurons, possibly contributing to our current cognitive abilities. (Total brain interconnectivity correlates moderately well with IQ.) 

Makes one wonder about the possibilities for further changes…

 

From New Scientist:

Eichler’s group discovered that SRGAP2 duplicated itself 3.5 million years ago, well after humans and chimps diverged. One million years later, this “daughter” of the original gene underwent its own duplication and created a “granddaughter” copy. All three coexist in modern humans.

[…]

The effect of this genetic sabotage, however, was that the brain had more time to develop. Although the mouses brain itself didnt grow larger, the neurons in the neocortex changed to look like human brain cells, growing thick spines to exchange information with other cells. The neurons also formed 50 to 60 per cent more of these spines than normal mouse neurons do, which would likely increase the brains processing power.

via One gene helped human brains become complex – life – 03 May 2012 – New Scientist.

Sheer Numbers Gave Early Humans Edge Over Neanderthals

Early humans may have overwhelmed Neanderthals by dint of sheer numbers.  Of course, that begs the question of why homo sapiens had such larger numbers than our homo neanderthalensis cousins.

Between 35,000 and 45,000 years ago, Neanderthals in Europe and Asia were replaced by the first modern humans. Why and how this transition occurred remains somewhat controversial. New research from the journal Science suggests that sheer numbers may have played a large role in modern humans’ eventual takeover; archeological data shows that early populations of modern humans may have outnumbered Neanderthals by more than 9 to 1.

via Sheer Numbers Gave Early Humans Edge Over Neanderthals | Wired Science | Wired.com.