Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany.
J Biol Rhythms. 2012 Feb;27(1):37-47. doi: 10.1177/0748730411420246.
The ability to adapt to different environmental conditions including seasonal changes is a key feature of the circadian clock. Here, we compared the ability of 3 Drosophila melanogaster wild-type strains to adapt rhythmic activity to long photoperiods simulated in the laboratory. Fruit flies are predominantly crepuscular with activity bouts in the morning (M) and evening (E). The M peak follows dawn and the E peak follows dusk when the photoperiod is extended. We show that this ability is restricted to a certain extension of the phase angle between M and E peaks, such that the E peak does not delay beyond a certain phase under long days. We demonstrate that this ability is significantly improved by simulated twilight and that it depends additionally on the genetic background and the ambient temperature. At 20 °C, the laboratory strain CantonS had the most flexible phase angle between M and E peaks, a Northern wild-type strain had an intermediate one, and a Southern wild-type strain had the lowest flexibility. Furthermore, we found that the 3 strains differed in clock light sensitivity, with the CantonS and the Northern strains more light sensitive than the Southern strain. These results are generally in accord with the recently discovered polymorphisms in the timeless gene (tim) that affect clock light sensitivity.
适应不同环境条件（包括季节性变化）的能力是生物钟的一个关键特征。在这里，我们比较了 3 种黑腹果蝇野生型菌株适应实验室模拟长光周期的节律性活动的能力。果蝇主要是黄昏活动，在清晨（M）和傍晚（E）有活动爆发。当光周期延长时，M 峰紧随黎明，E 峰紧随黄昏。我们表明，这种能力仅限于 M 和 E 峰之间相位角的一定扩展，使得 E 峰在长日下不会延迟超过一定的相位。我们证明，这种能力通过模拟曙光显著提高，并且它还取决于遗传背景和环境温度。在 20°C 下，实验室品系 CantonS 在 M 和 E 峰之间具有最灵活的相位角，北方野生型菌株具有中等的相位角，而南方野生型菌株具有最低的灵活性。此外，我们发现 3 种菌株在时钟光敏感性方面存在差异，CantonS 和北方菌株比南方菌株对光更敏感。这些结果与最近发现的影响时钟光敏感性的 timeless 基因（tim）中的多态性大致一致。
