Sequence variability map of the MH class II region of the seahorse, based on the sequencing of alleles from a single heterozygous individual. Intron-exon structures of MH class IIα and IIβ are indicated as well as SNPs distinguishing the two full-length alleles (i.e. variability = 1). Note the presence of regions of repetitive sequence (An, Cn, CAn, Gn and Tn) as well as a 786 bp deletion in the region between the IIα and IIβ loci. Primers used in the amplification and sequencing of this region are indicated (see Table 1 for primer sequences). Full length sequences have been deposited in GenBank (KP259908, KP259909).