New research on mutation in yeast can enhance understanding of huma...( DURHAM N.H. Yeast a model organism ...),Health

DURHAM, N.H. Yeast, a model organism heavily relied upon for studying basic biological processes as they relate to human health, mutates in a distinctly different pattern than other model organisms, a finding that brings researchers closer to understanding the role of evolutionary genetics in human diseases and cancer. The study, by researchers from the University of New Hampshire, Indiana University, Harvard University, and the University of Utah, appears in Proceedings of the National Academy of Science (PNAS) Online Early Edition this week (June 16 20, 2008).

"In biology, the mutation is an absolutely fundamental process, essential to evolution but also the source of all genetic disease," says Kelley Thomas, associate professor of biochemistry and director of the Hubbard Center for Genome Studies at the University of New Hampshire. "Despite its importance, we still don't know much about the basic processes of mutation." Cancers are caused by mutations, as are inherited diseases like Huntington's disease and fragile X syndrome, the most common inherited form of mental retardation.

"If we know more about the patterns of mutation, we'd be able to better understand the origins of these diseases and maybe prevent them," says Thomas.

The researchers asked a fundamental question: "What is the baseline rate and spectrum of mutation in yeast?" They found that, like the previously studied mutations in the nematode Caenorhabditis elegans, the yeast Saccharomyces cerevisiae had a very high rate of mutation from generation to generation.

Its patterns of mutation, however, turned out to be unique. While C. elegans mutations were largely the result of inserting or deleting base pairs of DNA, yeast's patterns of mutation were characterized by changing one base pair for another. "That was really surprising, that we didn't find that adding or subtracting in yeast," says Thomas. He adds that the consequences of inserting and dele
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