In mid-December, Science
announced that the millimeter-long worm Caenorhadditis elegans
became the first animal to have its entire genetic structure sequenced.
Coming in at 97 million bases and over 19,000 different genes, C. elegans
might be the first animal to be completely sequenced, but it is unlikely
to be the last (about a dozen bacterial genomes have also been sequenced
as well as the genetic structure of yeast).
Already the sequencing effort
is providing important information. For example, evolutionary biologists
and geneticists long suspected that all life shared many key genes in
common. Comparing C. elegans to yeast, the two species share about
3,600 genes indicating that evolution at the genetic level is largely an
additive process (i.e. natural selection tends to cause additional genes
to build on existing genes rather than displace or reengineer existing
genes).
Analysis of the wormÂ’s genes
also yielded important information about how multi-cellular creatures
switch genes on and off to develop cellular structures that can communicate
and coordinate their activities.