Ultima Genomics, Inc.

Described herein are methods for determining a sequence of a region of interest from an mRNA molecule. Sequenced polynucleotides can include a barcode region, a homopolymer region (e.g., a poly-A region), and a target region associated with the mRNA molecule. According to some methods, the barcode region omits the same base present in the homopolymer region. According to some methods, extension of the primer used for sequencing is stalled within the homopolymer region. According to some methods, sequencing flow cycles and the different barcode regions of the polynucleotides configured are such that the primer is extended to the end of the barcode region across the plurality of polynucleotides before being extended into the homopolymer region. According to some methods, two primers or a cleavable primer is used to separately sequence the barcode region and the target region.

Described herein are methods synchronizing sequencing primers within a sequencing cluster and methods of generating long-range sequencing reads. The methods can include hybridizing primers to polynucleotide copies within a sequencing cluster; extending the primers through a first region of the polynucleotide copies using labeled nucleotides according to a sequencing flow order; extending the primers through a second region of the polynucleotide copies using one or more re-phasing flow steps that each include at least two different types of nucleotide bases; and extending the primers through a third region of the polynucleotide copies using labeled nucleotides according to the sequencing cycle. The rephasing flow steps may be initiated after a predetermined number of sequencing flow steps, after a measured sequencing signal strength falls below a predetermined sequencing signal strength threshold, or a measured sequencing signal-to-noise ratio falls below a sequencing signal-to-noise ratio threshold.

A double-stranded template nucleic acid molecule may comprise an adaptor, the adaptor comprising a mismatch portion. The mismatch portion may comprise a first mismatch sequence in a first strand and a second mismatch sequence that is not complementary to the first mismatch sequence in a second strand. When the double-stranded template nucleic acid molecule is amplified to generate a cluster of amplified strands, and the cluster sequenced to generate a sequencing read, the portion of the sequencing read corresponding to the mismatch portion may be analyzed to determine whether the cluster of amplified strands has derived from only one or both strands of the double-stranded template nucleic acid molecule. Disagreements at one or more loci in sequencing signals, base calls, or sequencing reads between the two strand derivatives in the cluster may be used to correct for sequencing error and improve sequencing accuracy.

Provided herein are systems and methods for determining a level of disease, methylation, minimal residual diseases (MRDs) in an individual. Provided herein are systems and methods for retaining double-stranded context of a double-stranded nucleic acid molecule during sequencing.

Methods for detecting a short genetic variant in a test sample are described herein. In some exemplary methods, the short genetic variant is called using one or match scores, which are determined using one or more sequencing data sets obtained from a test nucleic acid molecule, wherein the test sequencing data sets are determined by sequencing the test nucleic acid molecule using non-terminating nucleotides provided in separate nucleotide flows according to a flow-cycle order. Also described herein are methods of sequencing a test nucleic acid molecule using two or more different flow-cycle orders and/or extended flow cycle orders having five or more nucleotide flows per flow cycle.

The present disclosure provides methods and systems for processing nucleic acid samples. Methods for processing a nucleic acid sample may comprise providing a double-stranded nucleic acid molecule comprising a partially denaturable region; partially denaturing the partially denaturable region of the double-stranded nucleic acid molecule, thereby generating a region comprising two single strands; and hybridizing a priming sequence to a sequence of one of the single strands. The methods described herein may facilitate amplification without the need for a multitude of complex steps or numerous reagents.

Methods for detecting a short genetic variant in a test sample are described herein. In some exemplary methods, the short genetic variant is called using one or match scores, which are determined using one or more sequencing data sets obtained from a test nucleic acid molecule, wherein the test sequencing data sets are determined by sequencing the test nucleic acid molecule using non-terminating nucleotides provided in separate nucleotide flows according to a flow-cycle order. Also described herein are methods of sequencing a test nucleic acid molecule using two or more different flow-cycle orders and/or extended flow cycle orders having five or more nucleotide flows per flow cycle.

The present disclosure provides methods and processes for increasing the efficiency and accuracy of nucleic acid sequencing using techniques such as polymerase chain reaction (PCR). The methods described herein can be used to achieve clonal amplification even with a greater than Poisson distribution of beads and/or nucleic acid templates into an emulsion. A PCR method may comprise generating a partition (e.g., a droplet) comprising at least two beads and/or at least two nucleic acid molecules and generating clonal amplification products corresponding to the nucleic acid molecule, at least a subset of which may be attached to a bead.

Described herein are methods for determining a sequence of a region of interest from an mRNA molecule. Sequenced polynucleotides can include a barcode region, a homopolymer region (e.g., a poly-A region), and a target region associated with the mRNA molecule. According to some methods, the barcode region omits the same base present in the homopolymer region. According to some methods, extension of the primer used for sequencing is stalled within the homopolymer region. According to some methods, sequencing flow cycles and the different barcode regions of the polynucleotides configured are such that the primer is extended to the end of the barcode region across the plurality of polynucleotides before being extended into the homopolymer region. According to some methods, two primers or a cleavable primer is used to separately sequence the barcode region and the target region.

Methods for detecting a short genetic variant in a test sample are described herein. In some exemplary methods, the short genetic variant is called using one or match scores, which are determined using one or more sequencing data sets obtained from a test nucleic acid molecule, wherein the test sequencing data sets are determined by sequencing the test nucleic acid molecule using non-terminating nucleotides provided in separate nucleotide flows according to a flow-cycle order. Also described herein are methods of sequencing a test nucleic acid molecule using two or more different flow-cycle orders and/or extended flow cycle orders having five or more nucleotide flows per flow cycle.