Figure 1

Figure 1

Nocturnin gene structure in Osteichthyes. Full-genome duplications are indicated as 3R (Teleostei specific) and 4Rc (Cyprininae specific). Proposed model for the exon–intron structure of the gene encoding nocturnin in different Osteichthyes clades, and its transcription into mRNA (dashed lines). The I, II and III indicate the alternative splicing variants. # indicates the alternative transcription start sites. Exons are represented by boxes and introns by lines. Angled blue lines indicate alternative splicing of the first exon (exon 1a, exon 1b or exon 1c) in mature mRNA. The length (bases pair, bp) of exons (inside the boxes) and introns (above lines) is indicated for the Lepisosteus oculatus gene. Lost exons during evolution of Ostariophysi and Cyprininae are represented by red crosses. Question marks indicate unconfirmed loss of variant III in the noc-a paralogues of cyprinines. Light pink and cyan backgrounds on Cyprininae nocturnin names indicate matrilineal and patrilineal origin, respectively.