Since pedigree data were available, it was possible to determine the combinations of Mafa-B alleles on one chromosome (haplotype). Most haplotypes contain two major alleles, in combination with one or two alleles with lower levels of transcription, or minors, as based on the number of picked clones within a PCR sample. Unfortunately, it can not be excluded that some alleles are incorrectly considered as minors due to primer inconsistencies. Haplotypes with only one or three majors were also observed. Moreover, it was possible to extend these Mafa-B combinations with specific -A region configurations/haplotypes that were described in an earlier study (Otting et al. 2007 ). Combinations of Mafa-A and -B alleles that are segregating, and are observed in at least two related animals are listed (Table 2) . Although more than one Mafa-A gene is present on the cynomolgus chromosome, only alleles of the highly polymorphic Mafa-A1 locus are provided for sake of convenience. Six additional Mafa-A/B haplotypes were seen in only one animal, whereas nine sequence combinations were ambiguous, and are not listed in the table. Further analyses on these animals, and on their offspring are needed to find out if these are recombinations.