Scientists come up with most detailed picture of an organisms evolutionary process

January 17th, 2009 - 4:55 pm ICT by ANI  

Washington, Jan 17 (ANI): New evidence from a study of yeast cells has resulted in the most detailed picture of an organisms evolutionary process to date.

The evidence was found by a Texas A and M University chemical engineering professor, whose findings provide the first direct evidence of aspects, which up until now have remained mostly theory.

Working with populations of yeast cells, which were color-coded by fluorescent markers, Katy Kao, assistant professor in the Artie McFerrin Department of Chemical Engineering, and Stanford University colleague Gavin Sherlock were able to evolve the cells while maintaining a visual analysis of the entire process.

Their research shows the evolutionary process to be much more dynamic than initially thought, with multiple beneficial adaptations arising within a population.

These adaptations, Kao explained, triggered a competition between these segments, known as clonal interference.

Its the first direct experimental evidence of this phenomenon in eukaryotic cells, or cells with nuclei, and it contrasts the widely accepted classical model of evolution, which doesnt account for simultaneously developing beneficial adaptations, she said.

Instead, that model adopts a linear approach, theorizing that a population acquires such adaptations successively, one after another.

Rather than a competition occurring, the model posits a complete replacement of one generation by another better-adapted generation.

That wasnt the case in Kaos sample.

Observing the color-coded yeast populations as they evolved to respond to their environment, Kao saw some colors expand while others contracted a sign that adaptations were occurring.

But, rather than one segment of the population continuing to shrink until it was completely replaced, some segments were able to compete long enough to acquire further adaptations.

When this happened, Kao explained, these populations of cells, once apparently less-fit, began to swell while once-dominant populations started to shrink.

This constant reduction and burgeoning of populations signaled the development of multiple beneficial adaptations and a subsequent competition by the cells that acquired them, according to Kao.

Essentially, we were watching evolution in action, Kao said.

Were watching evolution in real time. Were actually seeing a mutation that shows these things have adapted and seeing their population thrive and expand from this adaptation. This is how evolution works, she added. (ANI)

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