She observed the effects of the transposition of Ac and Ds by the changing patterns of coloration in maize kernels over generations of controlled crosses, and described the relationship between the two loci through intricate microscopic analysis. She concluded that Ac controls the transposition of the Ds from chromosome 9, and that the movement of Ds is accompanied by the breakage of the chromosome. When Ds moves, the aleurone-color gene is released from the suppressing effect of the Ds and transformed into the active form, which initiates the pigment synthesis in cells. The transposition of Ds in different cells is random, it may move in some but not others, which causes color mosaicism. The size of the colored spot on the seed is determined by stage of the seed development during dissociation. McClintock also found that the transposition of Ds is determined by the number of Ac copies in the cell.
she observed the effects of the transposition of ac and ds by the changing patterns of coloration in maize kernels over generations of controlled crosses and described the relationship between the two loci through intricate microscopic analysis she concluded that ac controls the transposition of the ds from chromosome 9 and that the movement of ds is accompanied by the breakage of the chromosome when ds moves the aleurone-color gene is released from the suppressing effect of the ds and transformed into the active form which initiates the pigment synthesis in cells the transposition of ds in different cells is random it may move in some but not others which causes color mosaicism the size of the colored spot on the seed is determined by stage of the seed development during dissociation mcclintock also found that the transposition of ds is determined by the number of ac copies in the cell