A single-celled alga has evolved a crude form of multicellularity in the lab – a configuration it never adopts in nature – giving researchers a chance to replay one of life's most important evolutionary leaps in real time.
This is the second time researchers have coaxed a single-celled organism into becoming multicellular – two years ago, the same was done with brewers yeast. But the alga is an entirely different organism, and comparing the two could explain how the transition to multicellular life happened a billion years ago.
Multicellularity has evolved at least 20 times since life first began, but no organisms have made the leap in the past 200 million years, so the process is difficult to study. To replicate the step in the lab, Will Ratcliff, an evolutionary biologist at the Georgia Institute of Technology in Atlanta, and colleagues grew 10 cultures of a single-celled alga, Chlamydomonas reinhardtii. Every three days, they centrifuged each culture gently and used the bottom tenth to found the next generation. Since clusters of cells settle faster than single ones, this meant that they effectively selected for algal cells that had a tendency to clump together.
Read the full article here: http://www.newscientist.com/article/dn24535-alga-takes-first-evolutionary-leap-to-multicellularity.html