1. A method for producing nucleic acid probes complementary to a target sequence comprising the steps in the following order: (a) obtaining double stranded polynucleotides that contain sequences complementary to the target sequence and to repetitive sequences; (b) fragmenting said double stranded polynucleotides into fragments; (c) denaturing said fragments into single stranded polynucleotides; (d) hybridizing said repetitive sequences with a subtractor sequence to form a mixture of double strands and single strands; (e) cleaving said double stranded polynucleotides; and (f) amplifying said single stranded polynucleotides to form a probe set complementary to the target sequence.