After confirming the accuracy of the sequence (it covers 98% of the genome and has an accuracy of 99.98%), the researchers turned to the substance of the genome. Examining the two worm genomes side by side, scientists can quickly spot genes and flag interesting regions for further investigation. Analyzing the organization of the two genomes, Stein et al. not only found strong evidence for roughly 1,300 new C. elegans genes, but also indications that certain regions could be "footprints of unknown functional elements." While both worms have roughly the same number of genes (about 19,000), the C. briggsae genome has more repeated sequences, making its genome slightly larger. The size is estimated to be just over 100 million base pairs, about 1/30 the size of the human genome.
Because the worms set out on separate evolutionary paths about the same time mice and humans parted ways--about 100 million years ago, compared to 75 million years ago--the authors could compare how the two worm genomes have diverged with the divergence between mice and humans. The worms' genomes, it seems, are evolving faster than their mammalian counterparts, based on the change in the size of the protein families (C. elegans has more chemosensory proteins than C. briggsae, for example), the rate of chromosomal
Contact: Barbara Cohen
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