Whole heads of Canton-S flie were seperated from bodies using liquid nitrogen freezing and sieve (0.710 mm) seperation. About 100 seperated whole fly heads were homoginized in 0.5 ml Trizol (Invitrogen). Then 0.1 ml chloroform was added. After vigorous vortexing and centrifugation at 12,000 g for 15 minuntes, 0.28 ml of the aquous phase sample was transfered to a new tube, mixed with 0.25 ml 2-isopropanol, then loaded on a RNeasy column (Qiagen), the RNA sample was further purified by the RNeasy kit. Targets were produced using standard Affymetrix procedures from about 10 ug of total RNA. 10 ug of cRNA was used for hybridization. This sample is whole head sample 4 of Canton-S. Keywords = Drosophila Keywords = mRNA tagging Keywords = photoreceptor cell-specific genes
