The Mhc-A region-derived class I alleles of the animals in this cohort were sequenced in an earlier study (Otting et al. 2007 ). In those analyses, primers were used that are specific for Mhc-A alleles in macaques. However, in some animals the Mafa-A1 locus was not amplified by this primer set. In the present study, RT-PCR was performed with macaque Mhc-B-specific primers, and with the generic class I primers for those animals previously lacking a Mafa-A1 sequence. The use of these generic primers resulted in the detection of six new alleles for the Mafa-A1 locus, and one for both the Mafa-A2 and the -A5 genes (Table 1) , and as such extends the earlier reported data.