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Phoenix666 [soylentnews.org] writes:

Researchers studying a sponge-like creature say they’ve found evidence that one mutation more than 600 million years ago may have paved the way for multicellular life [futurity.org].

Mutations can lead to good or bad results, or even to a combination of the two, says Ken Prehoda, a professor in the chemistry and biochemistry department at the University of Oregon.

“Proteins are the workhorses of our cells, performing a wide variety of tasks such as metabolism,” he says. “But how does a protein that performs one task evolve to perform another? And how do complex systems like those that allow cells to work together in an organized way, evolve the many different proteins they require?

“Our work suggests that new protein functions can evolve with a very small number of mutations. In this case, only one was required.”

Prehoda’s team began looking at choanoflagellates with the help of Nicole King’s group at the University of California, Berkeley. Choanoflagellates are a group of free-living, single-celled organisms considered to be the closest living relative of animals.

These sponge-like, seawater-dwelling organisms have a short, outward-facing squiggly tail called a flagellum that allows them to move and gather food. Choanoflagellates exist both in a single-celled solitary form, but also as multi-cellular colonies.

Prehoda and colleagues then used ancestral protein reconstruction, a technique devised at the by co-author Joseph W. Thornton, a biologist at the University of Chicago. By using gene sequencing and computational methods to move backward in the evolutionary tree, researchers can see molecular changes and infer how proteins performed in the deep past.

Original study [doi.org].

Original Submission