Shedding our penis spines helped us become human, DNA study hints

Guardian ^ | Wednesday 9 March 2011 | Ian Sample

[Cardhu]

Genetic comparison with chimps suggests that losing chunks of DNA – including one associated with penis spines and facial whiskers – played a crucial role in making us human.

Scientists have identified a clutch of subtle genetic changes that have shaped our minds and bodies into the unique form that sets humans apart from chimpanzees and the rest of the animal kingdom.

The work by researchers in the US represents a landmark in a search that has occupied philosophers and scientists for millennia and one that goes to the heart of understanding what it means to be human.

The findings offer up the humbling conclusion that the secret of human success may owe more to what we lost along the path of evolution, rather than anything we gained.

When the human genome was first deciphered more than a decade ago, some scientists expected to find extra genes that explained why humans had an intellectual edge over their closest living relatives and other species. But since diverging from chimpanzees around seven million years ago, it turns out that our human ancestors lost several hundred snippets of DNA, which together led to traits that are uniquely human, the researchers claim.

In ditching these chunks of DNA, our ancient ancestors lost facial whiskers and short, tactile spines on their penises. The latter development is thought to have paved the way for more intimate sex and monogamous relationships. The loss of other DNA may have been crucial in allowing humans to grow larger brains.

Intriguingly, hardly any of the lost DNA was from genes, which make the proteins that are the building blocks of life. Instead, the missing DNA came from areas of the genome that regulate where and when certain genes are active.

[frithguild]

Google is your friend. :-)

[colorado tanker]

Perfect Friday thread!

[RightOnTheLeftCoast]