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Experimental evolution of multicellularity: the movies

In case you missed the news coverage by Carl Zimmer in the New York Times, Jeff Akst in The Scientist, and Ed Yong on Nature's news site, among others, our paper on experimental evolution of multicellularity has just been published in Proceedings of the National Academy of Sciences. It's open access, so you can read all the details yourself.

In nature, multicellularity has only evolved a few about 25 times, and it took billions of years. But Mike Travisano (a fellow faculty member in Ecology Evolution and Behavior) and postdoc Will Ratcliff (who earned a PhD with me recently) came up with a simple and repeatable way to speed the process enough to study under lab conditions: selection for rapid settling in liquid media, starting with unicellular yeast. They kindly invited Mark Borrello and me to participate in this exciting project, which also depended on hard work by undergrads Kristin Jacobsen, Mitch Hoverman, and Amanda Muehlbauer and funding from the National Science Foundation. We have also had some support for preliminary genetic analysis (in progress) from the College of Biological Sciences at the University of Minnesota.

The best collection of links related to this work is at the Microbial Population Biology (Micropop) website, which brings together people and projects from the laboratories of Mike Travisano, Tony Dean, and me. I particularly recommend the videos showing reproduction of snowflake-like multicellular yeast via smaller multicellular propagules -- think of plants reproducing from fragments, rather than seeds -- and genetic stability of the multicellular trait, shown by regrowth of multicellular clusters from enzymatically isolated single cells.

I gave some background for this work in an earlier post, when Elizabeth Pennisi wrote about it for Science.

Update: two scientists criticize some of our claims, and Will Ratcliff responds, on Carl Zimmer's blog, here.

Comments

The is a wonderful example of experimental evolution and the power of inclusive fitness theory. One issue though with this analysis is that several texts have found that multicellularity has evolved more than "a few times"; Bourke (2011) notes that there have been 25 independent origins of multicellularity.

Are you serious GM? I think you are interpreting that statement too literally. The paper clearly states that "multicellularity has evolved repeatedly in unrelated phylogenetic
groups."

Ford, I've enjoyed reading all the coverage and especially the paper. Congrats to you and the others on all the exposure.

Jason,

I am referring to the sentence in the post that begins, "In nature, multicellularity has only evolved a few times, and it took billions of years." By saying "only a few times" seems to suggest less than 10. I was not referring to the paper itself.

As I stated, the work is remarkable.

I think GM has a point and will revise the post. This reminds me of discussions I had with a German-speaking postdoc who kept revising my use of "few" in a paper. The problem turned out to be the difference between "few" (not many) and "a few" (not zero) in English, a distinction which is apparently not found in German.

GM, after reading my previous comment, I believe I misread the tone of your original comment and that it was ultimately my tone that came across as distasteful. For that I apologize.

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