Fig. 4. snk encodes the zebrafish Na⁺K⁺ ATPase Atp1a1a.1 protein. Predicted structure of the Na⁺K⁺ ATPase Atp1a1a.1 protein. Red dot in the M2-M3 loop represents site of amino acid change from glycine to aspartate at residue 271 in the snk^to273a mutant. RT-PCR and sequencing was performed on the snk mutants from 3 snk carrier clutches (107 embryos), embryos from a snk sibling non-carrier clutch (76 embryos) and a wild-type clutch (79 embryos). In 100% of embryos, snk mutants, identified phenotypically, showed the G to A mutation, which would result in the glycine to aspartate amino acid change, whereas all wild-type embryos showed the normal G nucleotide.