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MHC ANTIGEN-BINDING LOCUS SHOWS STRONG SIGNAL OF SELECTION AND HIGH VARIABILITY IN FUNDULUS HETEROCLITUS POPULATIONS
Citation:
Cohen, S. MHC ANTIGEN-BINDING LOCUS SHOWS STRONG SIGNAL OF SELECTION AND HIGH VARIABILITY IN FUNDULUS HETEROCLITUS POPULATIONS. Presented at 25TH Annual Eastern Fish Health Workshop, Plymouth, MA, April 10-14, 2000.
Description:
The major histocompatibility system provides a unique genetic locus in vertebrates to assess genetic diversity and to look for the effects of selecti.on on the immune system. Fish population studies using MHC are fairly new, and thus far they have focused on endangered populations and aquacultural stocks. I measured levels and patterns of MHC diversity in wild estuarine fish populations including one location where the fish are under severe chemical stress and also show unusual patterns of parasitism. I isolated intron 1 and exon 2 of MHC Class 1 DRB1 using degenerate PCR primers designed from other fish species. The locus is extremely polymorphic within Fundulus populations, showing. 7-28% sequence divergence in the coding region within a population. Populations show strong signals of selection at . the inferred antigen binding region Fish from the New Bedford Harbor EPA superfund site show unusual patterns of parasitism including increased infection rates and unusual host locations. I found a 13% incidence of unusually divergent MHC alleles that may be associated with parasitism.