Mutation produces a new enzymatic function - evolution of new traits

Some people claim that mutations can only cause the loss of function, not the addition of new functions. However, in an exceptionally well-designed experiment, using thousands of generations of Escherichia coli bacteria, Lenski and co-workers have been able to observe a new function appear, by which E. coli can use citrate as an energy source (which normal E. coli cannot do). See here for more on this experiment and the results.

This is not a new result, but it seemed wise to point toward it again in this blog. Thank you for reading!