The genetic blueprint at the heart of life may be divided into "research and development" and "production" sections, according to an author of a new study in this week's "Science" that compares genetic material in yeast, roundworms, insects and humans.

The distinction may help shunt the random genetic changes that cause evolution onto areas of the DNA where such changes have a better chance of benefitting the organism (the "R&D" section) and away from areas where they would more likely harm it (the "production" section).

"The great paradox of evolution is that you have many established functions to maintain in an organism, and how can you be conservative about those functions while experimenting to discover new and possibly advantageous gene functions?" says Edward Hedgecock, biology professor at The Johns Hopkins University.

If it is confirmed, the theory could aid researchers in their efforts to analyze genetic information from humans and other species.

With support from the National Institutes of Health, Hedgecock and other researchers conducted an extensive computerized comparison of the sequence of genetic information, known as genomes, found in yeast, the roundworm C. elegans and other nematodes, the fruit fly Drosophila, and humans.

New species arise throughout evolution. Comparing their genomes can therefore provide "snapshots" of the development of DNA at various points in evolutionary history. Since portions of DNA are used as instructions for building proteins, researchers can compare the details of these "snapshots" to get a feel for when life first developed various proteins.

If, for example, a gene for a protein is common to yeast and to animals, Hedgecock explains, then the protein's birth date was before the emergence of multicellular organisms.

Hedgecock and his coauthors focused most of their attention on proteins involved in the creation of
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Contact: Michael Purdy
mcp@jhu.edu
410-516-7160
Johns Hopkins University
9-Feb-2000