Affymetrix of Santa Clara, Calif., has received US Patent No. 8,586,312, "Methods of using an array of pooled probes in genetic analysis." The patent describes arrays of polynucleotide probes patterned in three discrete regions. A first region bears a pool of polynucleotide probes consisting of first and second probe sets. A second region contains the first probe set without the second probe and a third region bears the second probe set without the first probe set.