Dpy. Unc. meT7 is an end-to-end-to-end fusion of chromosomes III, X, and V. The right end of III is fused to the left end of X, and the right end of X is fused to the left end of IV. Constructed by crossing eT5 and mnT12. meT7 homozygotes produce 92% viable progeny. meT7 heterozygotes are Him and produce many dead eggs.