The human major histocompatibility complex (MHC) class III region contains
57-60 structural genes spanning 654-759 kb of genomic DNA. Analysis of the
sequence identities of the human and mouse genomic regions between NOTCH4 a
nd complement C2 yields important information on the locations of the codin
g and regulatory sequences. I also provides insights into the relationship
between protein function and level of sequence conservation, and on the clu
stering of genes with related functions.