Scheme for the design of the custom array. The sequences complementary to the artificially synthesized 25-mer oligodeoxyribonucleotides are shown on the left (A). The sequence highlighted in red is representative for the diversity of probe length as follows. Middle sequences (B) are variant probes the length of which is changed from 25- to 14-mer. In each 25-mer probe, the original sequence is shortened progressively by one nucleotide at the 5' terminal end. The sequence highlighted in red is representative for the diversity of mismatch position and types of mismatched nucleotide as follows. Sequences on the right (C) show three perfect match probes and all possible single base substitutions arranged at each nucleotide.