Fig. 5. Bisected thoraces viewed with polarized light. Canton-S control flies (A) display the stereotyped configuration of six DLMs (blue). Seventy-nine percent of the hemithoraces from Sply⁰⁵⁰⁹¹ homozygotes have a reduced number of fibers. This representative hemithorax (B) has only three fibers, which exhibit compensatory hypertrophy. Excision of the transposon reduces the occurrence of aberrant fiber count to 13% as shown in this Sply^14a homozygote (C). lace^k05305 homozygotes generally (76%) have a normal complement of DLMs; however, occasionally only one large fiber is present as shown (D). A single copy of lace^k05305 reduces the occurrence of aberrant hemithoraces in the Sply⁰⁵⁰⁹¹ homozygotes to 63% (E), and 92% of Sply⁰⁵⁰⁹¹, lace^k05305 double mutants are normal (F). A DLM schematic shown below [adapted, with permission, from Hartenstein (Hartenstein, 1993)].