Experimental design. Biological replicates, sample pooling and validation of presented gene expression comparison of the four inbred mouse strains were performed using strategy described by the scheme. Five independent biological replicates of microarray were prepared for each strain of mice. Total RNA isolated from the striatum of three animals was pooled. Each pool of total RNA was separately converted to cRNA and hybridized to a single microarray. Samples from two separate groups of animals from each strain of mice were used in qPCR experiment.