The MHC region in amphibian genome assemblies and on linkage maps. The location and length of the MHC region comprising APG, MHC-II, extended MHC-II gene, and all annotated MHC-I genes located within 100 Mb. MHC genes in the four newt species were annotated manually in this study; manual annotation of MHC in A. mexicanum is from Migalska et al. (2025), and MHC genes in X. laevis are from the publicly available annotation of the v. 10.1 genome assembly. Note that, although in all newt genomes, the MHC region is on the same chromosome, naming and coordinates follow the original genome assemblies; numbers at the ends of chromosomes indicate coordinates (in Mb) in the original assemblies. Comparative linkage maps of L. vulgaris and T. cristatus (France et al. 2025) indicate that the MHC region is located on the opposite ends of LG1 in these species—cM 101 and 15, respectively.