Expression of ftzhs.T:Hsap\MYC, following a heat shock 2 hours after egg laying, affects segmentation of the embryo. In 42% of these embryos, a complete pair-rule phenotype is seen, in which only T2, A1, A3, A5, A7 are present. In ~27% of embryos, a partial pair-rule phenotype is seen, in which not all denticles are affected.