Abstract: A system can identify a source of a copy number change in a sample based on a comparison of properties of the sample to a second sample. Sequence reads categorized in bins of a genome are obtained from a first sample and a second sample. A determination is made whether each bin categorized by the sequence reads is statistically significant based on, for example, a bin sequence read count, an expected sequence read count, and a yin variance estimate for the bin. Likewise, a determination is made whether, for the first sample and the second sample, each segment of the genome is statistically significant based on a segment sequence read count and a segment variance estimate. Statistically significant bins and segments of the first sample are compared to statistically significant bins and segments of the second sample, and a copy number change source is identified based on the comparison.

Abstract: A system and machine readable medium for nucleic acid sequencing includes disposing template polynucleotide strands in defined spaces disposed on a sensor array, at least some of the template polynucleotide strands having a sequencing primer and a polymerase operably bound therewith; exposing the template polynucleotide strands to a series of flows of nucleotide species flowed according to a predetermined ordering; and determining, for each of the series of flows of nucleotide species, how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands, wherein the predetermined ordering (a) is not a series of consecutive repetitions of a 4-flow permutation of four different nucleotide species, (b) is not specifically tailored to a particular combination of a particular template polynucleotide strand to be sequenced and a particular sequencing primer to be used, and (c) comprises a phase-protecting flow orde

Abstract: A method for nucleic acid sequencing may include disposing a plurality of template nucleic acid molecules in a plurality of defined spaces disposed on a sensor array, at least some of the plurality of template nucleic acid molecules having a sequencing primer and a polymerase operably bound therewith; advancing one or more nucleotide species over the plurality of template nucleic acid molecules with the sequencing primer and the polymerase operably bound therewith; measuring a signal generated by nucleotide incorporations resulting from advancing the one or more nucleotide species; and exposing the plurality of template nucleic acid molecules to a cleaving reagent subsequent to the advancing and measuring. The cleaving reagent can remove labeling reagents attached to the one or more nucleotide species.

Abstract: For some cancers, microsatellite instability (MSI) in cell-free DNA can indicate the presence of a cancer in a subject. Subjects can generate a DNA sample for analysis to determine a likelihood that MSI exists and, thereby, determine a likelihood that the sample includes cancer. A system determines a likelihood that the sample includes MSI by selecting a set of markers from the sample and determining if those markers include MSI associated with cancer. The system determines if a marker is significant in by calculating: a viability score, a significance score, an entropy score, and a divergence score. The processing system determines an instability score representing a likelihood that the sample includes MSI based on the determined marker significances. Based on the instability score, the processing system can determine that a sample includes MSI and inform a method of treatment for the subject.

Abstract: A method for sequencing a nucleic acid template includes: (a) performing a first sequencing process including flowing nucleotides and/or reagents to the nucleic acid template according to a first predetermined ordering of nucleotides and/or reagents to obtain a first sequencing result; (b) after the first sequencing process, performing a second sequencing process including flowing nucleotides and/or reagents to the nucleic acid template according to a second predetermined ordering of nucleotides and/or reagents to obtain a second sequencing result, the second predetermined ordering of nucleotides and/or reagents being different from the first predetermined ordering of nucleotides and/or reagents and at least one of the first and second predetermined orderings of nucleotides and/or reagents being designed for repeat sequencing; and (c) determining a sequence of bases corresponding to at least a portion of the nucleic acid template using both the first sequencing result and the second sequencing result.

Abstract: A processing system uses a Bayesian inference based model for targeted sequencing or variant calling. In an embodiment, the processing system generates candidate variants of a cell free nucleic acid sample. The processing system determines likelihoods of true alternate frequencies for each of the candidate variants in the cell free nucleic acid sample and in a corresponding genomic nucleic acid sample. The processing system filters or scores the candidate variants by the model using at least the likelihoods of true alternate frequencies. The processing system outputs the filtered candidate variants, which may be used to generate features for a predictive cancer or disease model.

Abstract: A processing system uses a Bayesian inference based model for targeted sequencing or variant calling. In an embodiment, the processing system determines first depths and first alternate depths of first sequence reads from a cell free nucleic acid sample of a subject. The processing system determines second depths and second alternate depths of second sequence reads from a genomic nucleic acid sample of the subject. The processing system determines likelihoods of true alternate frequency of the cell free nucleic acid sample and of the genomic nucleic acid sample. Using the first likelihood, the second likelihood, and one or more parameters, the processing system determines a probability that the true alternate frequency of the cell free nucleic acid sample is greater than a function of the true alternate frequency of the genomic nucleic acid sample.

Abstract: A method for evaluating variant likelihood includes: providing a plurality of template polynucleotide strands, sequencing primers, and polymerase in a plurality of defined spaces disposed on a sensor array; exposing the plurality of template polynucleotide strands, sequencing primers, and polymerase to a series of flows of nucleotide species according to a predetermined order; obtaining measured values corresponding to an ensemble of sequencing reads for at least some of the template polynucleotide strands in at least one of the defined spaces; and evaluating a likelihood that a variant sequence is present given the measured values corresponding to the ensemble of sequencing reads, the evaluating comprising: determining a measurement confidence value for each read in the ensemble of sequencing reads and modifying at least some model-predicted values using a first bias for forward strands and a second bias for reverse strands.

Abstract: In some embodiments, the disclosure relates generally to methods, as well as related, systems, compositions, kits and apparatuses, for nucleic acid analysis that involve the use of modified nucleotides, including terminator nucleotides and/or tagged nucleotides, in a template-dependent nucleotide incorporation reaction. In some embodiments, the nucleic acid analysis can be conducted at a single reaction site, or at a plurality of reaction sites in an array of reaction sites. Optionally, the array contains a plurality of reaction sites having about 1-100 million, or about 100-250 million, or about 200-500 million, or about 500-900 million, or more reaction sites. Optionally, each reaction site is in contact with, operatively coupled, or capacitively coupled to one or more sensors that are ion-sensitive FETs (isFETs) or chemically-sensitive FETs (chemFETs) sensors. Optionally, the reaction sites are in fluid communication with each other.

Abstract: Systems and method for determining variants can receive mapped reads and determine a distribution of matched-filter residuals distribution from a plurality of reads at a homopolymer region. The distribution of matched-filter residuals can be fit to uni-modal and bi-modal models. Based on the model that best fits the distribution of matched-filter residuals, the heterozygosity of the sample and the absence or presence of an insertion/deletion in the homopolymer can be determined.

Abstract: An embodiment of a method of analyzing data from processed images of biological probe arrays is described that comprises receiving a plurality of files comprising a plurality of intensity values associated with a probe on a biological probe array; normalizing the intensity values in each of the data files; determining an initial assignment for a plurality of genotypes using one or more of the intensity values from each file for each assignment; estimating a distribution of cluster centers using the plurality of initial assignments; combining the normalized intensity values with the cluster centers to determine a posterior estimate for each cluster center; and assigning a plurality of genotype calls using a distance of the one or more intensity values from the posterior estimate.

Abstract: A kit for use with a nucleic acid sequencing instrument can include a plurality of combinatorial barcodes sequences meeting the following criteria: each of the combinatorial barcode sequences comprise a plurality of iterations of a sequence motif, where the sequence motif comprises a first nucleotide base from a first group of nucleotide bases followed by a second nucleotide base from a second group of nucleotide bases, the first group and the second group differing from each other; and the plurality of combinatorial barcode sequences is at least 1,000,000 different barcode sequences.

Abstract: Methods for analyzing signal data generated by sequencing of a polynucleotide strand using a pH-based method of detecting nucleotide incorporation(s). In an embodiment, the method comprises formulating a function that models the output signal of a representative empty well of a reactor array. A time transformation is applied to the empty well function to obtain a time-warped empty well function. The time-warped empty well function is fitted to an output signal from the loaded well representative of a flow that results in a non-incorporation event in the loaded well. The fitted time-warped empty well function can then be used to analyze output signals from the loaded well for other flows.

Abstract: An embodiment of a method of analyzing data from processed images of biological probe arrays is described that comprises receiving a plurality of files comprising a plurality of intensity values associated with a probe on a biological probe array; normalizing the intensity values in each of the data files; determining an initial assignment for a plurality of genotypes using one or more of the intensity values from each file for each assignment; estimating a distribution of cluster centers using the plurality of initial assignments; combining the normalized intensity values with the cluster centers to determine a posterior estimate for each cluster center; and assigning a plurality of genotype calls using a distance of the one or more intensity values from the posterior estimate.

Abstract: A compression method includes measuring a waveform associated with a chemical event occurring on a sensor array, wherein the waveform comprises at least one region associated with expected measured values and at least one region associated with unpredictable measured values; applying a first compression process to the waveform, the first compression process including an averaging of one or more frames in one or more portions of the waveform; applying a keyframe delta compression to the frame-averaged data; forming a compressed data structure including a keyframe and calculated differences subsequent to the keyframe; and storing one or more compressed data structures in memory.

Abstract: Methods for analyzing signal data generated by sequencing of a polynucleotide strand using a pH-based method of detecting nucleotide incorporation(s). In an embodiment, the method comprises formulating a function that models the output signal of a representative empty well of a reactor array. A time transformation is applied to the empty well function to obtain a time-warped empty well function. The time-warped empty well function is fitted to an output signal from the loaded well representative of a flow that results in a non-incorporation event in the loaded well. The fitted time-warped empty well function can then be used to analyze output signals from the loaded well for other flows.

Abstract: A system and machine readable medium for nucleic acid sequencing includes disposing template polynucleotide strands in defined spaces disposed on a sensor array, at least some of the template polynucleotide strands having a sequencing primer and a polymerase operably bound therewith; exposing the template polynucleotide strands to a series of flows of nucleotide species flowed according to a predetermined ordering; and determining, for each of the series of flows of nucleotide species, how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands, wherein the predetermined ordering (a) is not a series of consecutive repetitions of a 4-flow permutation of four different nucleotide species, (b) is not specifically tailored to a particular combination of a particular template polynucleotide strand to be sequenced and a particular sequencing primer to be used, and (c) comprises a phase-protecting flow orde

Abstract: A compression method includes measuring a waveform associated with a chemical event occurring on a sensor array, wherein the waveform comprises at least one region associated with expected measured values and at least one region associated with unpredictable measured values; applying a first compression process to the waveform, the first compression process including an averaging of one or more frames in one or more portions of the waveform; and applying a second compression process to the waveform, the second compression process including a truncating of data corresponding to a portion of the waveform that is not related to a nucleotide incorporation component of the waveform.

Abstract: A method for nucleic acid sequencing includes disposing template polynucleotide strands in defined spaces on a sensor array, at least some of the template polynucleotide strands having a sequencing primer and a polymerase operably bound therewith; exposing the template polynucleotide strands to a series of flows of nucleotide species flowed according to a predetermined ordering; and determining, for each of the series of flows of nucleotide species, how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands, wherein the predetermined ordering (a) is not a series of consecutive repetitions of a 4-flow permutation of four different nucleotide species, (b) is not specifically tailored to a particular combination of a particular template polynucleotide strand to be sequenced and a particular sequencing primer to be used, and (c) comprises a phase-protecting flow ordering.

Abstract: A method for preparing a homopolymer recalibration panel includes: extracting, from a set of amplicons used in sequencing-by-synthesis, a set of candidate amplicons satisfying a first set of criteria, wherein the first set of criteria includes amplicons known to belong to high-confidence regions of a reference genome with no variants; and selecting, from the set of candidate amplicons, a reduced set of amplicons satisfying a second set of criteria, wherein the second set of criteria includes amplicons that together comprise at least a minimal threshold number of homopolymers of each homopolymer length between a predetermined minimal homopolymer length and a predetermined maximal homopolymer length for one or more of homopolymer types A, T, C, and G.