Saturday, January 21, 2012

evolving multicellularity

Multicellular Yeast from thescientistllc on Vimeo.

The Scientist | In as little as 100 generations, yeast selected to settle more quickly through a test tube evolved into multicellular, snowflake-like clusters, according to a paper published today (January 16) in Proceedings of the National Academy of Sciences. Over the course of the experiment, the clusters evolved to be larger, produce multicellular progeny, and even show differentiation of the cells within the cluster—all key characteristics of multicellular organisms.

“It’s very cool to demonstrate that [multicellularity] can happen so quickly,” said evolutionary biologist Mansi Srivastava of the Whitehead Institute for Biomedical Research in Massachusetts, who was not involved in the research. “Looking at the fossil record, we learned it took a very long time whenever these different transitions to multicellularity happened. Here they show it can happen very quickly.”

“[The study] was provocative,” agreed biochemist Todd Miller of Stony Brook University in New York, who did not participate in the work. “It’s a different way of attacking the problem [of how multicellularity evolved]—coming from a simple system that doesn’t normally do this and seeing what it takes to make it do it.”

The evolution of multicellular life has long intrigued evolutionary biologists. Cells coming together and cooperating for the good of the group goes against basic Darwinian principles. Yet multicellularity has evolved some two dozen times independently in nature, and has shaped the world as we know it.

But because most transitions to multicellularity happened more than 200 million years ago, many questions remain about how it happened. What were the ecological conditions that drove the transitions? And how did organisms overcome the conflicts of interest that accompany any sort of cooperative effort?


nanakwame said...

And this a gem
To Etta Johnny Otis and Jimmy Castor: Blanketing white/Snow fell at last/Color of wake