Photoperiodic induction of gene expression in Drosophila.

Young Drosophila females respond to low temperature and short photoperiod by developmental arrest of the ovaries. This form of reproductive diapause is a winter adaptation. Here we used Affymetrix microarrays to study global expression in female heads associated with long vs. short day. Within 8 hr after eclosion, flies were transferred to vials and maintained in light boxes illuminated by a 4W fluorescent bulb at 12.5°C under either long (16 hr) or short (10 hr) photoperiod. After for 12 days, femlaes were collected 4 hr after lights-on (ZT4).