Fig. 1: Structure of SCNN1 genes in select Cetartiodactyla.

A–D The genes SCNN1A, SCNN1B, SCNN1G and SCNN1D, respectively. Exons 2–13 are numbered according to the nomenclature by Gettings et al.¹⁷ with exons 2 and 13 encoding the first and second transmembrane domain of each ENaC subunit, respectively. Only exons are drawn to scale. Exon sizes are outlined with respect to the Alpaca (Vicugna pacos) as a reference and insertions and deletions are highlighted. The size of exon 13 is shown up to the corresponding STOP codon in V. pacos. Non-canonical splice donor/acceptor motifs (AC/GC) flanking the exons are indicated in black font, whereas mutated splice sites are indicated in orange. Stop codons are marked with a red X. The dashed box indicates a fusion of exons 11 and 12 of the SCNN1D gene due to mutation of the splice donor following exon 11 in Ovis aries. Exon colour code: light blue = marine species; turquoise = amphibious species; green = terrestrial species.