Figure 1.—

Morphology of polytene chromosomes in JIL-1 and Su(var)3-7 double mutant backgrounds. Polytene chromosome preparations from third instar male and female larvae were labeled with Hoechst to visualize the chromatin. Note the misalignment and intermixing of interband and banded regions and the extensive coiling and folding of the chromosome arms in JIL-1^z2/JIL-1^z2 (z2/z2) mutant chromosomes as compared to wild type (wt). The male X chromosome (X) was particularly affected and no remnants of banded regions were discernible. In JIL-1 and Su(var)3-7 double mutant backgrounds from male and female JIL-1^z2 Su(var)3-7^7.1A/JIL-1^z2 (z2, 3-7^7.1A/z2) and JIL-1^z2 Su(var)3-7¹⁴/JIL-1^z2 (z2, 3-7¹⁴/z2) larvae, the polytene chromosome morphology was indistiguishable from that of JIL-1^z2/JIL-1^z2 homozygous null mutants.