ANALYSIS OF PHYLOGENETIC AFFINITIES IN THE TRITICINAE BY PROTEIN ELECTROPHORESIS

Crude seed-protein extracts of wheat and wheat relatives were fractionated by electrophoresis on polyacrylamide gels. Homology of fractions in the resulting spectra was used as a criterion of genetic affinity among the species and among their genomes. The spectra of Triticum monococcum (AA), T. dicoccum (AABB) and T. aestivum (AABBDD) confirmed evidence from conventional methods that the A and B genomes are different, that the dicoccum A genome is only partially homologous with the monococcum genome, and that the affinity between T. dicoccum and T. aestivum involves the A and B genomes about equally. They also showed the monococcum genome to have more affinity with the aestivum A or both A and D, than with the dicoccum A genome. Protein homologies permitted discrimination of distant as well as close affinities: the spectra of T. monococcum (AA) and Secale cereale (EE) showed no homologous fractions (r = 0.05), while the spectra of T. dicoccum and T. durum (both AABB) showed 10 homologous and 5 sub-homologous fractions out of 15 (r = 0.92). Previous evidence that an amphiploid spectrum comprises essentially the sum of the fractions in its parental spectra was verified by the dissimilar spectra of T. aestivum (AABBDD) and S. cereale (EE) which accounted for all of the fractions of their amphiploid hybrid, Triticale (AABBDDEE). The effect of each parent upon the amphiploid spectrum was proportional to the number of genomes it contributes.