Saunders D S, Henrich V C, Gilbert L I
Department of Zoology, University of Edinburgh, Scotland.
Proc Natl Acad Sci U S A. 1989 May;86(10):3748-52. doi: 10.1073/pnas.86.10.3748.
The fruit fly Drosophila melanogaster displays an ovarian diapause that is regulated by photoperiod. Newly eclosed female flies (Canton-S wild type) exposed to short days (less than 14 hr of light per day) at 12 degrees C (or 10 degrees C) enter a fairly shallow reproductive diapause. Females exposed to long days (16 hr of light per day) at the same low temperature undergo ovarian maturation. The short day induced diapause continues for 6-7 weeks under a 10:14 light/dark cycle at 12 degrees C but is terminated rapidly after a transfer to higher temperature (18 or 25 degrees C) or to long days (18:6 light/dark cycle). Females from three strains homozygous for alleles of the period (per) locus, reportedly arrhythmic for behavioral circadian rhythms, and females that possessed two overlapping deletions of per were also capable of discriminating between long and short days, although, when compared with the wild-type flies, the critical day length was shifted to shorter values by approximately 2 hr. It is concluded that the period locus is not causally involved in photoperiod time measurement.
果蝇黑腹果蝇表现出一种受光周期调节的卵巢滞育现象。新羽化的雌蝇（Canton-S野生型）在12摄氏度（或10摄氏度）下暴露于短日照（每天光照少于14小时）时会进入相当浅的生殖滞育状态。在相同低温下暴露于长日照（每天16小时光照）的雌蝇会经历卵巢成熟。在12摄氏度的10:14光/暗周期下，短日照诱导的滞育持续6至7周，但在转移到较高温度（18或25摄氏度）或长日照（18:6光/暗周期）后会迅速终止。来自三个周期（per）基因座等位基因纯合的品系的雌蝇，据报道其行为昼夜节律无节律，以及拥有两个重叠的per缺失的雌蝇，也能够区分长日照和短日照，尽管与野生型果蝇相比，临界日长大约缩短了2小时。得出的结论是，周期基因座与光周期时间测量没有因果关系。
