A pair of enhancer sequences cloned from a pair of DGRP strains (DGRP-737 and DGRP-820), each sequence representing a different SNP sequence (one with and one without a chromatin accessibility quantitative trait locus that affects a grh-binding site), and corresponding to release 5 genome coordinates 2L:20114900..20115700 , are fused upstream of a minimal Hsp70 promoter followed by EGFP, tagged at the C-terminal end with a nuclear localization signal.