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Research Digest Synopses of Research Articles Newly Sequenced Worm a Boon for Worm Biologists Caenorhabditis elegans, a 1-mm soil-dwelling roundworm with the two genomes, Stein et al. not only found strong evidence 959 cells, may be the best-understood multicellular organism on for roughly 1,300 new C. elegans genes, but also indications the planet. As the most “pared-down’’ animal that shares essential that certain regions could be “footprints of unknown functional features of human biology—from embryogenesis to aging—C. elements.’’ While both worms have roughly the same number of elegans is a favorite subject for studying how genes control these genes (about 19,000), the C. briggsae genome has more repeated processes. The way these genes work in worms helps scientists sequences, making its genome slightly larger. understand how diseases like cancer and Alzheimer’s develop in Because the worms set out on separate evolutionary paths humans when genes malfunction. With the publication of a draft about the same time mice and humans parted ways—about 100 genome sequence of C. elegans’ first cousin, C. briggsae, Lincoln million years ago, compared to 75 million years ago—the authors Stein and colleagues have greatly enhanced biologists’ ability to could compare how the two worm genomes have diverged mine C. elegans for biological gold. with the divergence between mice and humans. The worms’ Every organism carries clues to its molecular operating system genomes, it seems, are evolving faster than their mammalian and evolutionary past embedded in the content and structure of counterparts, based on the change in the size of the protein its genome. To unearth these clues, scientists examine d