MULTIPLEX DETECTION OF NUCLEIC ACIDS Russian patent published in 2020 - IPC C12Q1/68 

FIELD: biotechnology.

SUBSTANCE: described is a method for detecting fetal aneuploidy by quantifying a first chromosome or a chromosomal locus relative to a second chromosome or a chromosomal locus in a maternal cfDNA sample, where the sample contains a mixture of fetus DNA and mother from the pregnant woman's blood. Method comprises: contacting a sample with a first and a second set of probes, wherein each of the probes of the first set specifically recognizes a specific target sequence within the first chromosome or chromosomal locus, and wherein each of the probes of the second set specifically recognizes a specific target sequence within the second chromosome or chromosomal locus, providing conditions, in which target sequences in first and second chromosome or chromosomal locus are at least partially single-stranded, providing conditions for annealing and ligation, at which probes are hybridized with their target sequences and ligation products are generated, wherein each ligation product is a nucleic acid ring containing a ligation compound, providing conditions for replication of nucleic acid rings as a rolling ring, labeling RCA products prior to distribution thereof on the surface of the substrate, counting the number of first replication products as rolling a ring, where first rolling-type replication products are amplified from ligation products obtained using probes of first set to provide first count, counting the number of second rolling type replication products, where the second rolling type replication products are amplified from the ligation products, obtained using probes of the second set to provide a first count, and comparing the first and second counted amounts, thereby determining relative amounts of the first and second type of nucleic acids in the sample.

EFFECT: invention extends the range of means of detecting a nucleic acid (for example, a chromosome) of interest containing several unique target sequences, using several specific probes, which are amplified by ring-type amplification.

12 cl, 11 dwg, 3 ex