“Much of what living cells do is carried out by “molecular machines” – physical complexes of specialized proteins working together to carry out some biological function. (…) In a study published early online on January 8, in Nature, a team of scientists from the University of Chicago and the University of Oregon demonstrate how just a few small, high-probability mutations increased the complexity of a molecular machine more than 800 million years ago. By biochemically resurrecting ancient genes and testing their functions in modern organisms, the researchers showed that a new component was incorporated into the machine due to selective losses of function rather than the sudden appearance of new capabilities. (...) The increase in complexity was due to complementary loss of ancestral functions rather than gaining new ones. (...) “It’s counterintuitive but simple: complexity increased because protein functions were lost, not gained,” Thornton said. “Just as in society, complexity increases when individuals and institutions forget how to be generalists and come to depend on specialists with increasingly narrow capacities.” (…) - Amira from Bookmarklet

"The accumulation of simple, degenerative changes over long periods of times could have created many of the complex molecular machines present in organisms today. Such a mechanism argues against the intelligent design concept of “irreducible complexity,” the claim that molecular machines are too complicated to have formed stepwise through evolution. (...) “These really aren’t like precision-engineered machines at all,” he added. “They’re groups of molecules that happen to stick to each other, cobbled together during evolution by tinkering, degradation, and good luck, and preserved because they helped our ancestors to survive.” - Amira