Genetic correlation between the pre-adult developmental period and locomotor activity rhythm in Drosophila melanogaster

Biological clocks regulate various behavioural and physiological traits; slower circadian clocks are expected to slow down the development, suggesting a potential genetic correlation between the developmental period and circadian rhythm. However, a correlation between natural genetic variations in the developmental period and circadian rhythm has only been found in Bactrocera cucurbitae. The number of genetic factors that contribute to this genetic correlation is largely unclear. In this study, to examine whether natural genetic variations in the developmental period and circadian rhythm are correlated in Drosophila melanogaster, we performed an artificial disruptive selection on the developmental periods using wild-type strains and evaluated the circadian rhythms of the selected lines. To investigate whether multiple genetic factors mediate the genetic correlation, we reanalyzed previously published genome-wide deficiency screening data based on DrosDel isogenic deficiency strains and evaluated the effect of 438 genomic deficiencies on the developmental periods. We then randomly selected 32 genomic deficiencies with significant effects on the developmental periods and tested their effects on circadian rhythms. As a result, we found a significant response to selection for longer developmental periods and their correlated effects on circadian rhythms of the selected lines. We also found that 18 genomic regions had significant effects on the developmental periods and circadian rhythms, indicating their potential for mediating the genetic correlation between the developmental period and circadian rhythm. The novel findings of our study might lead to a better understanding of how this correlation is regulated genetically in broader taxonomic groups.