Friday, September 11, 2009

What Makes Us Human

It is understood that in the field of molecular evolution new genes can only evolve from duplicated or rearranged versions of preexisting genes. Furthermore, it seemed unlikely that evolutionary processes could produce a functional protein-coding gene from what was once inactive DNA.

But that view is changing as some evidence suggests that this phenomenon does in fact occur. It has been found that genes have arisen from non-coding DNA in yeast,flies, and also primates. No such genes had been found to be unique to humans until now, and the discovery raises questions about how these genes might make humans different from other primates.

One gene was identified in chronic lymphocytic leukemia. This is the first evidence for entirely novel human-specific protein-coding genes originating from ancestrally noncoding sequences. A non-coding sequence involves RNA (ncRNA) is a molecule that is not translated into a protein.In other words, a gene that was once dormant is now active.

The consequence of the finding is that while many coding sequences exist, there are some that are dormant in primates, but become active in humans. This makes us different

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