Schematic representation of WC1 exon-intron structure. Three structures were identified and were found to contain differing numbers of exons. Representative structures of WC1 genes containing (A) 20 exons (Type I; based on genomic sequence for WC1-5, GLEAN_13176) (B) 21 exons (Type II; based on genomic sequence for WC1-9, GLEAN_12191) (C) 15 exons (Type III, based on genomic sequence for WC1-11, GLEAN_09904 and GLEAN_12182) are shown. Exon numbers and SRCR domain numbers are indicated. Scale is shown in base pair increments beneath the schematic. Abbreviations are as follows: ID, inter-domain sequence; TM, transmembrane region; ICD, intracytoplasmic domain.