Transcriptomics in Nutritional Research The classical gene analysis approach, such as Northern blotting and real‐time RT‐PCR, can only analyze gene expression for a limited number of candidate genes at a time. DNA microarray technology allows us to measure the expression level of thousands of genes, or even entire genomes, simultaneously. A typical DNA microarray experiment includes a number of characteristic steps. 1. RNA extraction from a sample; 2. Reverse transcription of the RNA to obtain complementary DNA (cDNA) and labeling of the cDNA with specific dyes (usually fluorophores like Cyanine 3 and 5), or reverse transcription of the cDNA to obtain cRNA and labeling of the cRNA; 3. Hybridization of the labeled cDNA or cRNA onto the microarray under given conditions; 4. Washing the slides to remove non‐hybridized labeled oligonucleotides; 5. Using an appropriate scanning device to detect signal; and 6. Data analysis by bioinformatics tools....