Protein alignments of α1–α3 domains, conserved and positively selected sites. Representative sequences of MHC-I, MHC-I-like1 (L1), and MHC-I-like2 (L2) proteins predicted from newt genomes were aligned to the Xenopus laevis allele with resolved crystal structure (Xela-UAAg, PDB: 6A2B) and representative, highly expressed MHC-I sequences of Ambystoma mexicanum (Amme-04 and Amme-05) (Migalska et al. 2025). Positively selected sites identified in newts by FUBAR are shaded in gray; conserved anchoring residues are marked with orange stars. Species abbreviations: (Lihe) L. helveticus, (Livu) L. vulgaris, (Plwa) P. waltl, (Trcr) T. cristatus.