Fig. 1

Distribution of Tajima’s D in core promoter regions along chromosome arms of D. melanogaster. Black vertical bars show Tajima’s D of core promoter regions (CPRs) for all of the transcripts used. Red vertical bars show Tajima’s D of transcripts in which expression variation was significantly explained by sequence variation in CPRs. Blue horizontal lines indicate critical values at which the Tajima’s D values of CPRs are significantly higher or lower than zero (P < 0.01), based on a null distribution generated by coalescent simulations