Custom-designed Drosophila oligonucleotide array (Affymetrix, Santa Clara, CA). It contains 14,090 sequences representing 13,369 single transcripts encoding Drosophila proteins deposited in SWISS-PROT/TrEMBL databases (Celera Genome/BDGP Release no. 1) as well as prokaryotic and custom chosen control sequences. Each sequence is represented on the array by a set of 14 oligonucleotide probes of matching sequence and 14 probes with a single nucleotide mismatch. The oligonucleotides are 25mers. The Average Difference (Avg Diff) between the perfect match hybridization signal and the mismatch signal is proportional to the abundance of a given transcript [Lipshutz RJ: High density synthetic oligonucleotide arrays. Nat Genet 1999; 21:20-24]. Keywords = Drosophila melanogaster, full genome, Affymetrix, chip, genechip, oligonucleotide