Abstract: The present invention is related to a method for a simultaneous determination of the relative amounts of more than one target polynucleotide sequence and nucleotide variations in said targets. The method is carried out by separating and recording single-stranded probes, which have hybridized to the targets and which are determined and distinguished by their defined properties including size and optional detectable label. The probes are complementary to a region in the target that has a sequence being contiguous to the nucleotide variations to be determined. After being hybridized with affinity-tagged targets, the probes are attached to a solid support and purified. The target probe hybrids are elongated using enzyme-assisted elongations. The elongated probes are recorded after release from the solid supports and the amount of each of the targets and their nucleotide variations and the ratio of modified and modified target polynucleotide sequences are calculated from the recorded results.