Microarray technologyallows monitoring thousands of genes simultaneously in a specific tissue ofan organism, in different developmental stages or environmental conditions.Microarrays are very common in functional genomics experiments with both animalsand plant species, and they have been increasingly used also in different areasof livestock research, such as growth and metabolism, reproduction, immune responseto diseases and parasites, response to non-infectious stress factors (such asdietary restriction, exposure to toxic elements and other unfavorable environmentalconditions) as well as animal breeding. Such experiments, however, are stillconsiderably expensive and time consuming and, consequently, they are performedwith relatively small sample sizes. Nonetheless, microarray experiments areextremely complex, as they involve a number of laboratorial procedures suchas sample collection, RNA extraction, reverse transcription and labeling, andthe final hybridization. Hence, microarray assays require careful experimentalplanning and statistical data analysis. In this manuscript, basic principlesof experimental design for microarray studies are reviewed, as well as the mostcommon statistical and computational tools used for their analysis. In addition,some examples of application of microarray technology in animal science arediscussed, and some concluding remarks are presented afterward.
