[
Science,
1998]
The Caenorhabditis elegans genome sequence was surveyed for transcription factor and signaling gene families that have been shown to regulate development in a variety of species. About 10 to 25 percent of the genes in most of the gene families already have been genetically analyzed in C. elegans, about half of the genes detect probable orthologs in other species, and about 10 to 25 percent of the genes are, at present, unique to C. elegans. Caenorhabditis elegans is also missing genes that are found in vertebrates and other invertebrates. Thus the genome sequence reveals universals in developmental control that are the legacy of metazoan complexity before the Cambrian explosion, as well as genes that have been more recently invented or lost in particular phylogenetic lineages.AD - Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02114, USA. ruvkun@frodo.mgh.harvard.eduFAU - Ruvkun, GAU - Ruvkun GFAU - Hobert, OAU - Hobert OLA - engPT - Journal ArticlePT - ReviewPT - Review, TutorialCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Helminth Proteins)RN - 0 (Transcription Factors)SB - IM
[
Nature Neuroscience,
2004]
At first glance, the nervous systems of vertebrates and invertebrates seem bilaterally symmetrical, but on closer inspection left-right asymmetries become apparent. Humans, for example, show gross anatomical differences between right and left temporal lobes, and visual and language faculties are asymmetrically distributed between the two hemispheres. How these asymmetries arise during development remains something of a mystery (for review, see ref.1). In the nematode Caenorhabditis elegans, the AWC and ASE chemosensory neuron pairs are bilaterally symmetrical based on anatomical considerations, but nevertheless display asymmetrical gene expression patterns. A recent study in nature by Johnston and Hobert identifies a microRNA (miRNA) as a crucial mediator of this asymmetry in the ASE neurons.