PHENOTYPIC VARIABILITY IN PEDIGREED FAMILIES OF GOLDFISH REVEALED BY ALLOANTISERA AND AGGLUTINATION ASSAYS

Techniques of demonstrated usefulness for observing genetic variabilit y at the major histocompatibility complex (MHC) in avian and mammalian systems were evaluated for their potential utility in piscine systems by using goldfish Carassius auratus as a model. Three approaches to g enerating antisera and two methods of observing the results of hemaggl utination assays were evaluated. Seven full-sib families were produced , and red blood cells (RBCs) of goldfish family members were screened for reactivity with a panel of absorbed antisera consisting of fish an ti-fish, MHC-specific chicken anti-chicken, and chicken anti-fish sera . The pattern of presence or absence of agglutination after incubation of cell suspensions with the respective reagents in the panel of anti sera was regarded as the phenotype of the individual tested. Fifty dif ferent hemagglutination phenotypes were observed within and between fa milies. The large numbers of phenotypes observed within particular fam ilies may indicate (1) the need for additional absorptions in the prep aration of antisera useful for observing variability of the locus or l oci of issue, (2) segregation of additional sets of MHC or other haplo types in the tetraploid goldfish, or (3) segregates of non-MHC loci re acted with the antisera produced. Results of this study suggest that t he development of immune antisera and use of hemagglutination assays e ventually might be used to characterize genetic variability at the MHC in fish populations.