Expression patterns of period and timeless genes in mutants of Drosophila melanogaster under constant light condition

Genetic and molecular studies indicate that circadian rhythms are generated and regulated by the action of 8-10 genes in Drosophila. Two genes, period (per) and timeless (tim) and their products are found to be essential for the production of well known locomotor rhythms. The rhythmic expression patterns of per and tim in salivary glands of WT, vg and cry^b mutants at six time points were studied under constant light condition (LL). In wild type, expression of per and tim was noted at subjective day. However, in cry ^b mutants, the expression was found more in night and less in day times. In vg mutants the expression was similar to WT, but less intensive than WT. The similarity of expression in salivary gland in WT and vg suggests that similar kind of feedback mechanism could operate during developmental stages in peripheral tissues/oscillators. The difference in level of expression in cry^b flies indicates that photic transduction to the central/peripheral clock (s) is defective in cry^b flies as compared to WT and vg flies.