Methods are disclosed for adding adapters to fragmented nucleic acids for next generation sequencing, including providing numerical codes based on variable adapter molecular barcode lengths on both sides of the fragmented nucleic acids and identifying reads from the same fragment based on both barcodes. The methods and products allow for the amplification of the fragmented nucleic acids when there is a low yield of isolated fragmented nucleic acids and also for efficient and reliable detection of low-frequency mutations including in subpopulations of cells within a subject.

Methods are disclosed for adding adapters to fragmented nucleic acids for next generation sequencing, including providing numerical codes based on variable adapter molecular barcode lengths on both sides of the fragmented nucleic acids and identifying reads from the same fragment based on both barcodes. The methods and products allow for the amplification of the fragmented nucleic acids when there is a low yield of isolated fragmented nucleic acids and also for efficient and reliable detection of low-frequency mutations including in subpopulations of cells within a subject.

Disclosed is a method for determining a nucleotide sequence of a target nucleic acid. The method comprises: providing a pool of amplicons; sequencing each amplicon in the pool of amplicons to obtain sequence information of each amplicon; comparing a part of the sequence information of each amplicon with at least a part of the sequence of the target specific primer section, wherein the part of the sequence information of each amplicon is a sequence starting from position X-y and y is positive integer; determining whether the part of the sequence information of each amplicon comprises at least the part of the sequence of the target specific primer section; and determining accurate sequence of the target region using sequence information which comprises at least the part of the sequence of the target-specific primer section.

Disclosed is a method for determining a nucleotide sequence of a target nucleic acid. The method comprises: providing a pool of amplicons; sequencing each amplicon in the pool of amplicons to obtain sequence information of each amplicon; comparing a part of the sequence information of each amplicon with at least a part of the sequence of the target specific primer section, wherein the part of the sequence information of each amplicon is a sequence starting from position X-y and y is positive integer; determining whether the part of the sequence information of each amplicon comprises at least the part of the sequence of the target specific primer section; and determining accurate sequence of the target region using sequence information which comprises at least the part of the sequence of the target-specific primer section.

The present disclosure provide compositions, methods and kits for generating a set of combinatorial barcodes, and uses thereof for barcoding samples such as single cells or genomic DNA fragments. Some embodiments disclosed herein provide compositions comprising a set of component barcodes for producing a set of combinatorial barcodes. The set of component barcodes can comprise, for example, n×m unique component barcodes, wherein n and m are integers, each of the component barcodes comprises: one of n unique barcode subunit sequences; and one or two linker sequences or the complements thereof, wherein the component barcodes are configured to connect to each other through the one or two linker sequences or the complements thereof to produce a set of combinatorial barcodes.

The present disclosure provide compositions, methods and kits for generating a set of combinatorial barcodes, and uses thereof for barcoding samples such as single cells or genomic DNA fragments. Some embodiments disclosed herein provide compositions comprising a set of component barcodes for producing a set of combinatorial barcodes. The set of component barcodes can comprise, for example, n×m unique component barcodes, wherein n and m are integers, each of the component barcodes comprises: one of n unique barcode subunit sequences; and one or two linker sequences or the complements thereof, wherein the component barcodes are configured to connect to each other through the one or two linker sequences or the complements thereof to produce a set of combinatorial barcodes.

The present invention relates to a method for prenatal diagnosis using digital PCR, and more particularly to a method for providing information for diagnosis of chromosomal aneuploidy in a fetus, comprising: (a) extracting DNAs from pregnant woman's blood; (b) classifying the DNAs according to size to obtain DNAs having a size of 1,000 bp or less; (c) performing digital PCR using the obtained DNAs of step (b), for a control gene located on a chromosome not associated with chromosomal aneuploidy and a target gene located on a chromosome associated with chromosomal aneuploidy; (d) calculating a ratio of a quantitative digital PCR value of the target gene to a quantitative digital PCR value of the control gene; and (e) determining that when the ratio calculated in step (d) is 0.70-1.14, a chromosome number of the fetus is normal.

The present invention relates to a method for prenatal diagnosis using digital PCR, and more particularly to a method for providing information for diagnosis of chromosomal aneuploidy in a fetus, comprising: (a) extracting DNAs from pregnant woman's blood; (b) classifying the DNAs according to size to obtain DNAs having a size of 1,000 bp or less; (c) performing digital PCR using the obtained DNAs of step (b), for a control gene located on a chromosome not associated with chromosomal aneuploidy and a target gene located on a chromosome associated with chromosomal aneuploidy; (d) calculating a ratio of a quantitative digital PCR value of the target gene to a quantitative digital PCR value of the control gene; and (e) determining that when the ratio calculated in step (d) is 0.70-1.14, a chromosome number of the fetus is normal.

The present invention provides a method of determining integrity and/or quantity of cell free DNA (cfDNA) in a biological sample comprising amplifying target sequences with at least a first primer/probe set and at least a second primer probe/set, amplifying the target sequences of differing lengths, and monitoring for detection of the labels of the oligonucleotide probes, and determining the integrity and/or quantity of the cfDNA based on the level of detection of the label of the oligonucleotide probe from the first primer/probe set compared to the level detection of the label of the oligonucleotide probe from the second primer/probe set. The present invention also provides methods for generating a library with the cfDNA for sequencing and analysis.

The present invention provides a method of determining integrity and/or quantity of cell free DNA (cfDNA) in a biological sample comprising amplifying target sequences with at least a first primer/probe set and at least a second primer probe/set, amplifying the target sequences of differing lengths, and monitoring for detection of the labels of the oligonucleotide probes, and determining the integrity and/or quantity of the cfDNA based on the level of detection of the label of the oligonucleotide probe from the first primer/probe set compared to the level detection of the label of the oligonucleotide probe from the second primer/probe set. The present invention also provides methods for generating a library with the cfDNA for sequencing and analysis.