A method is described for controllably conducting complex PCR amplifications, wherein at least the following steps are conducted:

• a) PCR amplification with at least 50 primers of a first type (type 1) of different sequence, which are complementary to one of the strands of a random DNA sample, and also with a primer or a library of primers of a second type (type 2), which is complementary to the other strand of the DNA sample used, wherein the type 2 primers contain a first label (label 1);
• b) hybridizing of the amplified products to an oligomer array, which comprises oligonucleotides that hybridize to the primers utilized in the PCR reaction or to oligonucleotides that are complementary to these;
• or hybridizing of the amplified products to an oligomer array, which contains oligomers complementary to the primers utilized in the PCR reaction;
• c) length determination of the amplified products bound to the array by a second label (label 2) which can be correlated with the length of the respective DNA fragment, and which is different from the first label (label 1) in step a) and
• d) quantification of the signals originating from label 1 and label 2 at each site of the oligonucleotide array relevant for the analysis.