The situation for the HLA-B orthologues in macaque species is even more complicated. In one rhesus macaque, the MHC region was completely sequenced, yielding one complete haplotype of 5.3 megabase-pairs. On this haplotype, 19 distinct Mamu-B genes were present, of which 14 genes have the potential to code for bonafide proteins (Anzai et al. 2003; Daza-Vamenta et al. 2004; Bonhomme et al. 2008; Doxiadis et al. 2009 ). For the MHC of cynomolgus macaque a BAC-based contig map was constructed (Watanabe et al. 2007) . Although the degree of gene multiplication is less than in the rhesus macaque, this contig map still contains 12 distinct Mafa-B like loci. Sequencing studies at the cDNA level, however, have shown that only two or three genes per haplotype are transcribed at considerable levels (majors) in rhesus-and in cynomolgus macaques (Krebs et al. 2005; Otting et al. 2005 Otting et al. , 2008 Pendley et al. 2008) . At least one other B-like gene, characterised by low levels of polymorphism and transcription (minors), is present on all haplotypes. It has been designated Mamu-I, Mafa-I, and Mane-I in the respective species of macaques (Urvater et al. 2000; Robinson et al. 2003) . On the completely sequenced MHC-region of the rhesus macaque, this locus is designated as the Mamu-B3 gene (Daza-Vamenta et al. 2004; Doxiadis et al. 2009 ).