Stability of a position-effect variegation in normal and transdetermined larval blastemas from Drosophila melanogaster.

Male genital disks of a yellow-variegated genotype were implanted into the abdomens of adult females to test the stability of variegated clones in the blastemas formed by the implants. Upon reimplantation into metamorphosing larval hosts, test fragments of the proliferating blastemas differentiated into variegated organs, with yellow and wild-type areas. In later transfer generations clones were separated, which appeared stable for either wild type or yellow; variegation was no longer occurring. In all the lines differentiation occurred also into other organs (allotypic) than those characteristically formed by the genital disc (transdetermination). The absence of new variegation in these transdetermined organs is discussed as evidence against a reversal to the embryonic state in the cells of the transdetermining blastema. The variegation process seems not to be affected by, nor does it in this case influence, the process of transdetermination.