FISH MAJOR HISTOCOMPATIBILITY COMPLEX GENES - AN EXPANSION

The advent of polymerase chain reaction technology has provoked a larg e amount of progress in the field of fish major histocompatibility com plex (MHC) research. Many new teleost sequences have been reported in the last four years, including representatives of all classes of MHC g enes. While the intronexon structure of teleost MHC genes is now becom ing clear, the organisation of the genes within the teleost MHC is sti ll unclear. The sequences reported to date have been used for phylogen etic analysis and, due to their evolutionary position, are discussed i n relation to hypotheses regarding the origin of the MHC. Teleost MHC gene sequences are also examined to see if conserved features of both the nucleotide and amino acid sequences of higher vertebrate MHC genes are present. Differences in these features will reflect functional di fferences between teleost and mammalian MHC genes and may also have ev olutionary implications.