Phylogenetic analysis of vertebrate sodium pump catalytic subunits. Invertebrate sequences are used to root the tree. Gene duplication events are indicated by colored rhomboids. The tree is drawn to scale with the horizontal distances joining two nodes proportional to the number of amino acids substitutions. Scale bar, 10% substitution. The GenPept protein identification numbers for each gene are given. Genes in boldface represent those described in the present study. Partial sequences were not used in the analysis. For clarity, α1 sequences for mammals are grouped into one branch because the number of amino acid substitutions are small. The mammalian sequences includedEquus caballus (89128), Canis familiaris (1703466),Ovis aries (67958), Rattus norvegicus (92517),Homo sapiens (88220), and Sus scrofa (89248). Chromosome assignments for the zebrafish subunits were obtained by radiation hybrid mapping and are indicated at right.
