Correlated response to selection for faster pre-adult development on the circadian clocks of fruit flies drosophila melanogaster

Abstract

The Earth rotates around its axis creating alternate day/night cycles to which almost all organisms have adapted to create for themselves a distinct spatio-temporal niche (Pittendrigh, 1993; Sharma, 2003; Dunlap et al., 2004; Paranjpe and Sharma, 2005; Vaze and Sharma, 2013). It is widely believed that fluctuations in geophysical factors have aided the evolution of rhythms of a wide range of periodicities - tidal (~12 hours), semilunar (~14 days), lunar (~29 days) and annual (~a year) time scales. Among the variety of biological oscillations present in the living world, the most ubiquitous and hence the most widely studied ones are those with circadian periodicities (circadian rhythms: Latin: circa - approximately, dies - a day). Circadian clocks time the day-to-day behavioral repertoire of organisms and coordinate cellular and molecular cycles to ensure that they occur at suitable times of the day (Sharma, 2003; Paranjpe and Sharma, 2005; Vaze and Sharma, 2013). These clocks are known to synchronize metabolic processes with the environmental cycles to enable organisms to anticipate cyclic changes in their environment (Pittendrigh, 1993; Sharma, 2003; Dunlap et al., 2004; Vaze and Sharma, 2013).