A STUDY OF VARIABILITY IN THE MHC CLASS-II-BETA-1 AND CLASS-I-ALPHA-2DOMAIN EXONS OF ATLANTIC SALMON, SALMO-SALAR L

Variability in the most extracellular exons of Atlantic salmon MHC-Sas a class I and class II was studied by polymerase chain reaction (PCR) amplification followed by sequencing. The domains studied were class I alpha2 and class II beta1. The material used was genomic DNA of fish, mainly derived from the major Norwegian breeding pool, supplemented w ith some material from a minor breeder and a local river strain. The a nalysis revealed extensive variation, most individuals being heterozyg ous with at least two variants.