What does ordinary yeast have to say about evolution? Quite a lot, if the authors of a new study published in The Proceedings of the National Academy of Sciences are correct. The study showed that multicellular life can, in fact, evolve from single cells. Since life began as a single-celled organism nearly 4 billion years ago, the research is crucial to understanding how the plants and animals we see today came into existence.
A couple of years ago, a casual comment over coffee led researchers Will Ratcliff and Michael Travisano to pursue the problem of bridging the gap from unicellular to multicellular organisms. It was “just about the coolest thing we could do," they said in a written statement.
They gave it a shot, and eureka! They placed single-celled Brewer's yeast in a nutrient-rich test tube environment and the cells rapidly evolved to become multicellular creatures. In two months, the cells had clustered according to genotype, meaning cooperation was occurring--like a society, they evolved an organized division of labor. They also reproduced, and adapted to their environment, the steps setting the stage for multicellular life.
“A cluster alone isn’t multicellular,” Ratcliff said. “But when cells in a cluster cooperate, make sacrifices for the common good, and adapt to change, that’s an evolutionary transition to multicellularity.”
Travisano says their discovery could also lead to more advanced research in medicine.
“Our multicellular yeast are a valuable resource for investigating a wide variety of medically and biologically important topics,” he said in a written statement. “Cancer was recently described as a fossil from the origin of multicellularity, which can be directly investigated with the yeast system." Travisano also hopes that the research will lead to studies on development, the evolution of complex shapes and even the origins of aging.