Conservation of Gpr103 protein sequence in mammals and fish. A, Alignment of Gpr103 protein sequences from human (Hs, ENSG00000186867), mouse (Mm: Gpr103a, ENSMUSG00000058400; Gpr103b, ENSMUSG00000029917), and zebrafish (Dr: Gpr103a, ENSDARG00000039349; Gpr103b, ENSDARG00000068422), including the zebrafish Gpr103a 11 aa deletion mutant (d11) and Gpr103b 4 aa deletion mutant (d4). Predicted transmembrane domains are indicated by gray lines. The coding sequences of the zebrafish Gpr103a and Gpr103b mutants undergo frameshifts before the first and fifth predicted transmembrane domains, respectively, and thus are likely to be completely nonfunctional. B, Phylogenetic tree of human, mouse, and zebrafish Gpr103 receptors.