GAGG (Genetic Algorithm for Gene Gathering) is a new statistical method which allows to detect differentially expressed genes and to cluster them according to their expression profiles. This is a factorial method based on integer encoding of the projection variables. It allows to take into account the multivariate aspect of data. It requires the use of a genetic algorithm, and combines several statistical methods, such as PCA or k-means. The code is implemented in R language and consists in 5 functions. A main function GAGG, three internal functions GAGG1, GAGG2 and GAGG3 and a function which allows to visualize genes profiles PlotProfiles.