Larvae were reared on standard diet until early third instar, at which time they were washed and transferred to standard diet lacking yeast. The animals remained on this diet until four days after emergence, when one group of adults was switched back to standard diet containing yeast (group Y) while another remained on the diet lacking yeast (group NY). Flies from both groups were killed every hour for the next twelve hours, creating 24 samples across the two treatments. In addition, four samples of flies were killed just before the start of the time course and used as baseline replicates for the no yeast (NY) and yeast (Y) treatments. Baseline replicates were temporally ordered as noted for change-point analysis. No yeast (NY) treatment samples at hours four and eight did not yield microarray data due to insufficient RNA.
Total RNA was extracted from whole animals using Trizol (Invitrogen). Sample processing and microarray hybridization/scanning were performed at the Brown University Center for Genetics and Genomics according to Affymetrix protocol. Microarray data was normalized by DNA-Chip Analyzer (dChip, http://www.dchip.org), which utilizes an invariant difference selection (IDS) algorithm to construct a normalization relation. Keywords = insulin, diet, nutrition
