Evolution Proven in a Test Tube

A group of investigators from the University of Minnesota in Twin Cities managed to prove that highly-structured organisms can develop from inferior ones, when they watched single-celled microbes in a test tube evolve into multicellular lifeforms.

The latter were prefect capable of reproduction, which means that they met the criteria for the development of a new organism. This investigation is a major step towards understanding the origins of complex life.

UM expert and team leader Will Ratcliff decided to focus his group's attention on a certain species of yeast, which normally lives as a single-celled organism that produces single-celled offspring.

Over the course of several months, the experts subjected the organisms to conditions that were specifically designed to make life as a single-celled yeast difficult. Sure enough, within two months, the experts noticed the development of spiky, multicellular yeast forms.

In an announcement made at the Evolution 2011 conference on June 18, Ratcliff told colleagues that the evolutionary leap took place a lot faster than he and his team had originally anticipated. The study was “certainly the buzz of the conference,” University of Louisville expert Lee Dugatkin said.

“To be able to examine [the shift from single-celled to multicellular organisms] experimentally, in real time, in the lab, is extremely exciting,” the conference attendant added, quoted by Science News.

In order to make the yeast go multicellular, the experts used a centrifuge daily. They placed test tubes containing the microorganisms inside, and gave them enough spin to encourage the growth of heavier bodies. This could only be achieved by multicellular organisms.

Every day, the researchers went through the colonies, removing those cells that had failed to adapt to the day's ordeals. In the end, all that was left were years which had produced viable offspring.

Within two months, the UM team started observing bristly multicellular organisms that they called yeast snowflakes. Interestingly, when subjecting them to harsh conditions too, the researchers noticed an even more pronounced evolutionary response.

In fact, some of the multicellular organisms were acting to respond to the external stimuli as if they were part of the same organism. The team found this to be extremely interesting.