Genomics News

Protozoans with no dedicated stop codons?

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Image of the ciliate Condylostoma magnum surrounded by concentric rings of genetFrom Karen Zusi at The Scientist:

The genetic code—the digital set of instructions often laid out in tidy textbook tables that tells the ribosome how to build a peptide—is identical in most eukaryotes. But as with most rules, there are exceptions. During a recent project on genome rearrangement in ciliates, Mariusz Nowacki, a cell biologist at the University of Bern in Switzerland, and his team stumbled across two striking deviants.

Ciliates, complex protozoans with two nuclei, are known to translate RNA transcripts in unorthodox ways. Nowacki’s team, however, discovered that Condylostoma magnum and an unclassified Parduczia species had gone even further, reassigning all of the traditional “stop” codons (UGA, UAA, and UAG) to amino acids. “It didn’t make sense in the beginning,” says Nowacki. “Nobody would expect that there would be a stopless genetic code.”

“We were able to identify a novel biology in sea creatures, in creatures that were never looked at before,” says Nowacki. “It shows that [the genetic code] is not necessarily frozen and unambiguous.” More.

From My Science:

For biologists, the findings are not only interesting because they show that simple truths almost certainly prove wrong when it comes to cellular mechanisms. Nowacki thinks that they have accidentally found a transitional stage in the evolution of this special cell mechanism, highlighting evolution ’as it happens’. Studying this anomaly could help biologists understand how in some species the genetic code might gradually change. Maybe the biological language is not as frozen as we always thought.

Still moving beyond the world of gene fundamentalism, not looking back…

See also: Researchers: Early life stress shortens telomeres It’s amazing how genetic fundamentalism is falling by the wayside. The genome has got to be the worst thing that ever happened to the Gene, the Selfish Gene, and all that.

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One Reply to “Protozoans with no dedicated stop codons?

  1. 1
    wd400 says:

    What do you think this has to do with “gene fundamentalism”?

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