Timeless Gene in Drosophila Melanogaster

Timeless Gene in Drosophila Melanogaster

Circadian rhythms are physical, mental and behavioural changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment. A number of genes in Drosophila melanogaster are turned on when the animal is exposed to light. These include clock genes, whose products regulate the circadian clock. There are two key members of the clock genes which are period (per) timeless (tim). Activation of all of these genes requires that their promoters are bound by the protein transcription factors CLOCK encoded by the gene clock (clk) and CYCLE encoded by the gene cycle (cyc). The mechanism of Drosophila’s circadian clock starts by the formation of protein dimers using the PER and TIM proteins. A null mutation at tim would lead to arrhythmic individuals. This indicates that tim is required for the generation of rhythmic behaviour.
In this research paper, the ultimate purpose is to isolate and characterize six new timeless alleles which cause short or long period circadian rhythms in Drosophila. Drosophila mutations which have an influence on the circadian rhythms have been used for the isolation process of six new alleles of the timeless (tim) gene. All alleles appear to be semi-dominant. Four out of the six alleles result in long-period rhythms of 26-28 hours. On the other hand, two out of the six alleles cause short-period rhythms of 21–22 hours in constant darkness. The interaction between some tim alleles with per mutation was studied. This interaction indicates that such interactions are multiplicative. Multiplicative interactions mean that a given allele would use a fixed percentage, rather than a fixed number of hours, to change the period length of its genetic background. The long behavioural period of the timL1 allele is represented by a long molecular oscillation of per and tim RNA and protein levels, which is partly due to delayed nuclear translocation of TIML1 protein.
In conclusion, the six timeless alleles were...

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