Fig. 1.

Evolutionary history of SWS2 in teleost fishes. A first ancestral duplication of SWS2 into SWS2A and SWS2B happened at the base of the Neoteleostei (orange), which was followed by a second percomorph-specific duplication of SWS2A into SWS2Aα and SWS2Aβ (yellow). A lineage-specific SWS2B duplication was further discerned in lizardfishes (Aulopiformes). SWS2 gene synteny is schematically shown by blue polygons pointing out the direction of transcription, and the highly conserved HCFC1 upstream and LWS or GNL3L (in case of LWS loss) downstream genes are shown in gray; missing polygons equal gene loss. A dotted line with a question mark indicates a lineage for which genomic data of the target region could not be obtained. Gene conversion is depicted on an exon by exon basis in orange. Phylogenetic reconstruction, including age estimation, is based on the consensus of the most recent global fish phylogenies (19, 27). Fig. S1 shows the SWS2 gene phylogeny.