Encompasses the promoter, upstream regulatory region and part of the 5' UTR of mthl1, as well as the coding regions of SmG, RpS19a, CG9777 and rok.

Imprecise excision of the progenitor insertion, resulting in a deletion which extends from 14F2, X:16522115 (release 5 coordinates) to the the P{EPgy2}mthl1^EY16157 insertion site at 14F4, X:16535030 (release 5 coordinates). A portion of the original insertion, from nucleotide 6624 to the 3' P-element end remains associated with the deletion. The right breakpoint is within mthl1, generating the mthl1^YO17 allele.

Heterozygosity for Df(1)YO17 leads to a high frequency of defects in leg morphogenesis.

Zygotically embryonic lethal. Mutant embryos have uncoordinated ventral furrow apical constriction. Embryos exhibit defects in internalization of mesodermal cells or changes to the morphology of the ventral midline.