Figure 1.

Genomic map of the human and mouse major histocompatibility complex (MHC). A simplified schematic of the human and mouse MHC genomic regions (not drawn to scale). Annotations were taken from the mouse Genome Reference Consortium (GRC) m38/mm10 (2011) and human GRCh37/hg19 (2009) assemblies. The MHC spans approximately 3.6 Mb and is located on chromosome 6 of humans and 17 of mice. The classical MHCI genes (red) are highly polymorphic, whereas the non-classical MHCI genes (orange) are not. Class II and III genes are indicated by dark gray and light gray boxes, respectively, but have not been annotated here (see [9] for more detail on these regions). The light chain of MHCI molecules, β2-microglobulin, is encoded on a separate chromosome (15 in humans and 2 in mice). Classical MHC class I genes include HLA-A, HLA-B, and HLA-C in humans, and H2-K, D, L and B in mice. H2-L is very closely related to H2-D and appears to be present only in the BALB/c mouse strain. As such, H2-L is left out of current assemblies based on the C57BL/6 strain, but has been retained here for completeness. H2-B is a gut restricted classical MHCI gene. There are many nonclassical MHC class I genes that include MICA, MICB, HLA-E, HLA-G, HLA-F, and HFE in humans and MICA, MICB, Q, T, M and HFE in mice. The general arrangement of the MHC is similar between humans and rodents, with the main difference being that MHCI genes in mice have become separated at either end of the MHC by class II and III genes.