Monday, January 29, 2007

When Evolution Runs Backwards

A fascinating article appeared in the Jan. 13-19, 2007 edition of New Scientist. This was entitled "The Ancestor Within" by Michael LePage.

New evidence reveals the existence of many atavisms in nature. These are characteristics from ancient ancestors which suddently appear in modern species.

Prior to these discoveries, an axiom known as Dollo's Law was the widely held belief. Dollo's Law states that evolution can only run forward, not backward. However the preponderance of atavisms being discovered have caused scientists to question the accuracy of Dollo's Law.

It now appears that many characteristics of our ancient ancestors are not lost in our genome. Instead these genes are switched off, but can be switched on by mutation, or when environmental stress merits them being reintroduced in order to increase the chances of survival.

Michael's article is concise, and understandable to non-scientests, such as myself. If you are interested in evolution, then I think that you will enjoy it!

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