GeneScan fragment analysis of the H-2 Eb1 microsatellite marker (part of intron 2 of Eb1). The red peaks represent a part of the GeneScan 350 size standard (100, 139, and 150 bp). A, A 108-bp fragment is amplified in case of homozygous H-2^b haplotypes. B, A 108-bp and a 128-bp fragment are amplified in case of heterozygous H-2^b/H-2^aw18 alleles. C, A 128-bp fragment is amplified with a homozygous H-2^aw18 haplotype.