"Can Evolution Run in Reverse? A Study Says It’s a One-Way Street" -6

"Can Evolution Run in Reverse? A Study Says It’s a One-Way Street"
The New York Times. Retrieved at: http://www.nytimes.com/2009/09/29/science/29evol.html?ref=science
By CARL ZIMMER
Published: September 28, 2009

As evolution pushes forward, evolutionary biologists have always wondered if evolution could ever go backwards, back to how it first began. In 1905, a Belgian scientist named Louis Dollo, stated that no organism could ever go back to it’s former state, which was later known as Dollo’s Law. Scientist examined the evolution of one protein and claimed that there is no way for the proteins mutations to send it back to its first state. To test it out, they took the evolutionary history of an insect that started out with wings millions of years ago, and as it evolved it lost the wings, but then started to grow them again. They wondered if it was reverse evolution at the molecular level. They then tested with a protein that helps people deal with stress and they figured out how it evolved, yet they tried to reverse it, it became a dead receptor. They realized that the protein had some extra key mutations that involved the other mutations to become harder to reverse the evolution of the protein. Scientists say that maybe a simple mutation would have the ability to reverse but once it involves other mutations that twist and wind in each other to make it more complex, then that is when the reverse evolution becomes impossible.