Confirmation of known meiotic crossovers. The IBD enrichment process was applied to CEPH family grandparent-grandchild pairs. Amplification, labelling, hybridization and data analysis were performed as described in Methods, except standardization was by division of the normalized ratios by the standard deviation of the ratios of all clones on each array. For chromosome 1, the ratio values for the IBD-enriched DNA (solid lines) are compared with the regions where microsatellite genotypes are shared between a grandparent and grandchild (dotted lines); grandfather (GF)/child, blue and grandmother (GM)/child, red. The arrow indicates a meiotic recombination crossover region.