In the history of life, single-celled microbes have evolved into multicellular bodies at least 25 times. In our own lineage, our ancestors crossed over some 700 million years ago. In tomorrow's New York Times, I write about a new study in which single-celled yeast evolved into multicellular forms--completely with juvenile and adult forms, different cell types, and the ability to split off propagules like plant cuttings. All this in a matter of weeks. Check it out.
("Experimental evolution of multicellularity," William C. Ratcliff, R. Ford Denison, Mark Borrello, and Michael Travisano. Proceedings of the National Academy of Sciences. http://www.pnas.org/cgi/doi/10.1073/pnas.1115323109 )
Update: Here's a Twitter-Storify-blog follow up on some reactions to the study.