Para-albumin polymorphism: an unlinked two-locus system in rainbow trout.

Para-albumin (PALB), a new polymorphic protein system in rainbow trout, is described. Data from 20 ful-sib families established that the observed electrophoretic variability was controlled by two loci. Differential staining of two bands expressed by heterozygotes indicated that the PALB protein was a monomer and that the variability was the result of the expression of two alleles at each locus. The alleles at the two loci were further shown to be identical with regard to electrophoretic mobilities of the proteins. There was no evidence of linkage between the two loci. Consequently, it is concluded that the loci, PALB-1,2, reside on duplicate chromosomes that have retained their integrity since a tetraploidation event.