The invention of multicellularity

Multicellular yeast cluster. Photo courtesy of William Ratcliff.

In January, William Ratcliff and his colleagues from the University of Minnesota caused quite a stir with their study on the experimental evolution of multicellularity in yeast, published in PNAS. Many media covered the story, including the New York Times, Wired and Scientific American. Briefly, what they did was using artificial selection on unicellular yeast (the baker's yeast Saccharomyces cerevisiae) in order to create an obligate multicellular organism after many generations of selection. What is impressive is that it worked pretty well in all their different test cultures!

Multicellularity was invented several times during the history of life (Rokas, 2008), but since it happened a long time ago it is difficult to reconstruct the exact sequence of events. Experimentation on today's unicellular organisms, however, allows researchers to test mechanisms (and associated mutations) that could lead to a multicellular lifestyle. Of course, this cannot decide for good how the phenomenon occurred many millions years ago – which is not at all the author's claim – but this can prove that such mechanisms can occur, given that an appropriate selection pressure is present.

The publications of the American Academy of Microbiology

Published by AAM and ASM

Do you know your E. coli fact sheet well enough? If needed, you can set your record straight by having a look at one of the new publications of the American Academy of Microbiology: E. coli: Good, Bad & Deadly. This booklet is part of the FAQ series, a collection on important microbe-related topics written for a large public. 

To me, this series is a great resource to learn how to write for the layman: keep the writing engaging but do not cloud or sacrifice the facts. It contains such nice piece of writing as "E. coli is genetically promiscuous. It can exchange genes with other strains of E. coli and even other types of bacteria." The first sentence is funny and intriguing, whereas the second sentence explains briefly. The content of the whole booklet is substantial but not indigestible (about 6,000 words) and nicely illustrated.