The C. elegans genome is now nearing completion. I have just done a comprehensive search of C. elegans for P450s and named all the new sequences. There are 80 genes for P450s in C. elegans. Some of them are in large clusters with 10-13 genes, some of which are probably in operons. A small number (6-7) are pseudogenes. Since the whole genome of C. elegans is predicted to have about 16,000 genes, these P450s represent an unusually large subset comprising about 0.5% of the total. Some P450 clusters are in clusters of olfactory receptor related genes. Perhaps the P450s are in some way acting in concert with the olfactory receptors. Here is an excerpt from the bibliographic page with these sequences. There are 80 C. elegans P450s listed here, surpassing the known mouse and human complements. The C. elegans genome is now officially 77% complete. However, the amount of sequence in the Blast searchable database at Washington Univ. is 117Mb, more than the 100Mb size of the genome. Therefore, we can guess that this set includes all the P450 genes in C. elegans, but the distrubution is not even. Most P450 genes (43 genes) are on chromosome V. see additional info on C. elegans P450s see this list. To see the actual sequences go to the C. elegans sequence file. So far we are missing CYP11A and CYP11B, CYP17, CYP19, CYP21, CYP24 and CYP27A and CYP27B. Does C. elegans make steroids? The present evidence would suggest not. Does C. elegans have mitochondrial P450s? There is one probable mitochondrial P450 in C. elegans on cosmid ZK177 named CYP44. This sequence is incomplete, missing part of the I-helix and some sequence upstream of that. It probably cannot code for a functional gene.