The combination of SNPs 3 and 4 from the VT1.2 haplotype leads to a more robust mid-day siesta and delayed onset of evening activity compared to each SNP alone.

<p>Flies were exposed to 12∶12LD cycles for 5 days at 18° (A), 25° (B), or 29°C (C), and then kept in constant darkness (DD) for 7 days. Shown are the locomotor activity profiles for p{VT1.1-SNP3} (blue), p{VT1.2-SNP4} (green), and p{VT1.1-SNP3/4} (red) flies. Data recorded during the last three days of LD for individual flies (for each genotype, n > 50) was combined to obtain the group averages shown. To facilitate comparison, the peak value for evening activity for each genotype was set to 1 and all other values normalized. Grey shading, lights-off.