http://arstechnica.com/science/2012...ution-through-snapshots-of-40000-generations/ A follow-up report on the E coli speciation event reported in 2008. The team has gone back to preserved samples from every 500 generations, and genetically sequenced them to identify the points at which new mutations arose, and at which point those mutations started becoming predominant in the population. Still an open question regarding all of the steps that went on - as discussed at the end of the article, citrate-eating genes by themselves don't result in efficient citrate eating. Something else not yet understood is going on, too! More work to do!