The number of at least 24 distinct haplotypes is high, though they appear to be stable entities in this population of macaques; recombination was seldom observed. Only one case of crossing over between the Mhc-A and -B region is seen; Mafa-A1*03101 is present in conjunction with two different Mafa-B combinations (7 and 8 in Table 2 ). For eleven of the 24 Mafa-A/-B haplotypes it was possible to add an associated Mafa-I allele. Preliminary studies with DRB-microsatellites de Groot et al. 2008 ) indicate that the Mafa-A/B haplotypes are also linked to DRB-STR patterns. Further investigation should reveal whether in the future these animals and their offspring can be typed for the class I alleles by means of this extremely fast and accurate typing technique. In our cohort of animals, 16 Mafa-B alleles were detected that were already described in studies on other cynomolgus populations. To determine whether these alleles were arranged in haplotypes that are shared between populations a comparison was made. Three of these combinations were observed. Pendley and coworkers have already described the sharing of B*01201/B*05001/2 and B*04501/B*05101 allele-combinations in Indonesian and Mauritian cohorts (Pendley et al. 2008) , which illustrates that the Mauritian animals originate in the archipelago. Probably the animals were introduced to the island by merchant ships in the Dutch Golden Age (Sussman and Tattersall 1986) . Both haplotypes are present in our animals, and are listed, respectively, as 13 and 15 in Table 2 . The first one was extended to A1*06001/ B*0110102/B*01201/B*05001. In Pendley's cohort this combination of Mafa-B alleles is seen in an animal that also transcribes Mafa-A1*06003. This allele differs by two basepairs from Mafa-A1*06001. With genotyping based on reference-strand conformational analysis (RSCA), Krebs and co-workers found the combination B*0430101/ B*0440101/B*0460101 in a cohort of Mauritian animals (Krebs et al. 2005) . In our animals, however, we observed this set without B*0430101 (Table 2 , haplotype 14). It is possible that this allele is a minor, and therefore was probably missed in our cloning procedures. In the RSCA study the B*0430101 peak is also low in comparison to the peaks of the other two alleles. The three shared haplotypes were present in cohorts that, like most of our animals at the BPRC, originate in the Indonesian Islands. Sharing of haplotypes with the recently described Filipino cynomolgus macaques was not observed (Campbell et al. 2009 ).