loci with two different protein products
There are a small number of loci which code for two very different protein products. These include dicistronic mRNA operons and loci which have a few small exons in common then have alternate splicing leading to many different exons being used.
The details of some of these can be found in the WormBook chapter “Operon and non-operon gene clusters in the C. elegans genome”.
Previously, these have been curated as isoforms of a single gene. This was causing problems because the description of gene
function would be based on one isoform, leaving the other isoform undescribed or described incorrectly, based on the first isoform.
There are 42 C. elegans and 47 C. briggsae known loci that have now been split to have different Gene IDs.