In most animals, sequences that are alleles of the Mafa-I gene, the equivalent of the oligomorphic Mamu-I locus, were detected (Urvater et al. 2000) . The Mamu-I/Mafa-I locus has the characteristics of a nonclassical, with low levels of polymorphism and transcription. Only 12 Mafa-I sequences met the criterion of three identical clones, and eight of them have been submitted as novel alleles (Table 1) . Nevertheless, the Mafa-I gene appears to be present on all haplotypes.