Joint segregation of biochemical loci in salmonidae. III. Linkage associations in Salmonidae including data from rainbow trout (Salmo gairdneri).

The results of 107 pairwise examinations of joint segregation of biochemical and skin color loci in rainbow trout, Salmo gairdneri, are presented. Three examinations revealed significant nonrandom assortment: Idh-3 with Me-2, Ada-1 with G3p-3, and Mdh-3, with Mdh-4. We believe the first two instances to be cases of classical linkage and the latter instance to reflect pseudolinkage based on similar findings in Salvelinus. All known salmonid linkage associations are reviewed. The results of this summary indicate a high degree of genome conservatism among genera within the Salmonidae, which would seem to be in contrast to the highly plastic genome of this family based on karyotypic data. Data are presented which negate the view that Robertsonian fusion of homologous acrocentric chromosome arms was the preferred mode of metacentric formation in salmonid evolution.