Gene expression in Drosophila montana

We created a custom-made microarray for D. montana with 101 genes known to affect traits important in diapause, photoperiodism, reproductive behaviour, circadian clock and stress tolerance in model Drosophila species. This array gave us a chance to filter out genes showing expression changes during photoperiodic reproductive diapause in a species adapted to live in northern latitudes with high seasonal changes. The three samples for the microarray experiments included young females (“young”), 14 days old females cultured under diapause-preventing (“reproducing”) and 14 days old females cultured under diapause-inducing conditions (“diapausing”). Each of these samples had three replicates. The microarray contained 197 unique probe sequences representing 101 candidate genes and seven housekeeping genes. Some of the probes had two copies per array, in which case the averages of their signals were calculated. The Agilent control probes included 77 negative control probes and 200 spike-in probes (10 different probe types, each represented by 20 copies per array).