The Taxonomy of Developmental Control in Caenorhabditis elegans

Abstract

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.

Ancient origin of reggie (flotillin), reggie-like, and other lipid-raft proteins: convergent evolution of the SPFH domain

“…While such an ancestor cannot be formally ruled out, the large genetic distance between reggie/flotillin and reggielike proteins argues rather for their independent origin. This view is supported by the strikingly wide taxonomic gap where distant homologues fail to be detected, which goes beyond the existence of gaps in the databases and the masking of these ancestral gene forms through the accumulation of ancient genome rearrangements [50,51]. We believe that the most plausible scenario for the appearance of reggies/flotillins during evolution is the independent origin of a proto-reggie gene in early metazoans, which underwent a gene-genome duplication event to give rise to reggie-1 and -2 [1].…”

-Catenin-Dependent Wnt Signaling in C. elegans: Teaching an Old Dog a New Trick

“…The C. elegans genome contains a complement of core Wnt pathway components similar to those in flies and vertebrates, with some interesting differences (see Table 1) (Ruvkun and Hobert 1998;Eisenmann 2005;Hardin and King 2008). The C. elegans genome contains only five genes encoding Wnt ligands: lin-44, egl-20, mom-2, cwn-1, and cwn-2 (Shackleford et al 1993;Herman et al 1995;Rocheleau et al 1997;Thorpe et al 1997;Maloof et al 1999), a lower number than in other animals.…”

“…The worm genome encodes three Disheveled family members, MIG-5, DSH-1, and DSH-2, which function positively in Wnt signaling and which display genetic redundancy in several cases (Ruvkun and Hobert 1998;Walston et al 2004;Eisenmann 2005;King et al 2009). …”

“…elegans has four genes encoding Frizzled receptors, lin-17, mom-5, mig-1, and cfz-2 (Sawa et al 1996;Rocheleau et al 1997;Ruvkun and Hobert 1998;Zhao et al 2003), and a single Ryk/ Derailed receptor homolog encoded by lin-18 (Inoue et al 2004), which appear to function -14, mig-1, vps-35, cam-1(gf), egl-20, lin-17, mig-5, bar-1, pop-1, mab-5 Wild type QR.d QL.d as Wnt receptors. As with the Wnt ligands, for some processes the receptors display genetic redundancy such that Wnt reduction-of-function phenotypes are only seen when multiple genes are mutated (Gleason et al 2006;Pan et al 2006;Green et al 2008;Zinovyeva et al 2008).…”

Evolution of vertebrate appendicular structures: Insight from genetic and palaeontological data

“…For instance, the unicellular yeast genome encodes a total of $300 transcription factors, while the genome sequences of Caenorhabditis elegans and Drosophila reveal at least 1,000 transcription factors each (Ruvkun and Hobert, 1998;Aoyagi and Wassarman, 2000). There may be $2,000 transcription factors in humans (Vaquerizas et al, 2009).…”