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: Systems and methods for cancer subject tumor fraction estimation comprise obtaining a first plurality of nucleic acid fragment sequences from the subject's liquid biological sample. The first plurality of sequences represent cell-free nucleic acids in the liquid sample. A second plurality of nucleic acid fragment sequences is obtained from the subject's tumor sample. The second plurality of sequences represent nucleic acid molecules in the tumor. Smoothed noise rates, each determined using nucleic acid fragment sequences from non-cancer samples mapping to a corresponding allele position in a plurality of allele positions, are obtained. Variant allele counts and coverages are determined for the allele positions using the first plurality of sequences. Solid variant allele fractions are determined for the plurality of allele positions using the second plurality of sequences.

Abstract: Systems and methods are provided for determining relevant medical information about a cancer based on the distribution of fragment lengths of cell-free DNA sequenced from a biological fluid sample. In certain embodiments, the systems and methods are useful for segmenting a cancer genome, phasing alleles in a cancer genome, detecting the loss of heterozygosity in a cancer genome, assigning an origin of a variant allele, validating a sequencing mapping, and validating use of an allele in a cancer classifier.

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: A method for sequencing a polynucleotide sample having a barcode sequence, includes: introducing a series of nucleotides to the polynucleotide sample according to a predetermined flow ordering; obtaining a series of signals resulting from the introducing of nucleotides to the polynucleotide sample; and resolving the series of signals over the barcode sequence to render a flowspace string, wherein the flowspace string is a codeword of an error-tolerant code capable of distinguishing the barcode sequence from other barcode sequences in the presence of one or more errors.

Abstract: A predictive cancer model generates a prediction of cancer tissue source of origin for a subject of interest by analyzing values of one or more types of features that are derived from cfDNA obtained from the individual. Specifically, cfDNA from the individual is sequenced to generate sequence reads using one or more physical assays, examples of which include a small variant sequencing assay. The sequence reads of the physical assays are processed through corresponding computational analyses to generate small variant features and other features. The values of features can be provided to a prediction model that generates a prediction of cancer tissue source of origin and/or cancer presence.

Abstract: A system for nucleic acid sequencing includes a machine-readable memory and a processor configured to execute machine-readable instructions. The instructions, when executed by the processor, cause the system to expose template polynucleotide strands in a plurality of defined spaces of a sensor array to a series of flows of nucleotide species, the series comprising a sequence of random flows; and obtain, for each of the series of flows of nucleotide species, a signal indicative of how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands.

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: Systems and methods for processing sequencing data of ribonucleic acid (RNA) molecules from a test sample include obtaining a plurality of sequence reads each derived from a RNA molecule obtained from the test sample, filtering the plurality of sequence reads, identifying one or more candidate variants from the filtered plurality of sequence reads, determining a quality score for each of the identified one or more candidate variants, the quality score indicating a likelihood that the candidate variant is a false positive detection of a mutation in the RNA molecule, and outputting the one or more candidate variants having a quality score greater than a threshold quality score.

Abstract: Systems and methods for determining a source of a variant in a cell free nucleic acid sample include identifying a candidate variant in the cell free nucleic acid sample, determining a numerical score using a measure of first properties of a distribution of novel somatic mutations compared to a measure of second properties of a distribution of somatic variants matched in genomic nucleic acid, and determining a classification of the candidate variant using the numerical score, the classification indicating whether the candidate variant is more likely to be a new novel somatic mutation than a new somatic variant matched in genomic nucleic acid.

Abstract: A method for nucleic acid sequencing includes: disposing a plurality of template polynucleotide strands, sequencing primers, and polymerases in a plurality of defined spaces of a sensor array; exposing template polynucleotide strands to a series of flows of nucleotide species, the series comprising a sequence of random flows; and obtaining, for each of the series of flows of nucleotide species, a signal indicative of how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands.

Abstract: A method for nucleic acid sequencing includes: receiving a signal comprising measurements of a parameter measured in response to a plurality of nucleotide flows flowed in a space comprising a sample nucleic acid; normalizing the signal to obtain a normalized signal; adaptively normalizing the normalized signal to obtain an adaptively normalized signal; and predicting a sequence of base calls corresponding to the sample nucleic acid using the adaptively normalized signal.

Abstract: A method for sequencing a polynucleotide sample having a barcode sequence includes: introducing a series of nucleotides to the polynucleotide sample according to a predetermined order of nucleotide flows; obtaining a series of signals resulting from the introducing of nucleotides to the polynucleotide sample; and resolving the series of signals over the barcode sequence to render a flowspace string, wherein the flowspace string is a codeword of an error-correcting code that is (i) designed based on and adapted for use with the predetermined order of nucleotide flows, and (ii) capable of distinguishing any codeword in the error-correcting code from the other codewords in the error-correcting code in the presence of zero, one, and two errors.

Abstract: In some embodiments, the disclosure relates generally to methods, as well as compositions, systems, kits and apparatuses, for performing nucleotide incorporation, comprising: (a) providing a surface including one or more reaction sites containing a polymerase and a nucleic acid template that has, or is hybridized to, an extendible end; (b) performing a first nucleotide flow by contacting one or more of the reaction sites with a first solution including one or more types of terminator nucleotide; (c) incorporating at least one type of terminator nucleotide at the extendible end of the nucleic acid template contained within at least one of the reaction sites using the polymerase; and (d) detecting a non-optical signal indicating the nucleotide incorporation using a sensor that is attached or operatively linked to the at least one reaction site.

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: Systems and methods for determining a source of a variant include receiving a plurality of variants obtained from a biological sample, the variants being of unknown source upon receipt, and receiving, for each of the variants, a plurality of values for a plurality of covariates from the biological sample. The variants are input into a source assignment classifier to determine a source for each of the variants, the source being one of a plurality of possible sources. The source assignment classifier includes a plurality of coefficients associated with the plurality of covariates and a function that receives as input the values associated with each variant and the coefficients and outputs the determined source of each of the variants.

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: Methods and systems for detecting positive, neutral, or negative selection at a locus include obtaining a test sample of cell-free nucleic acids from a subject, preparing a sequencing library of the cell-free nucleic acids, sequencing the library to obtain a plurality of sequence reads, analyzing the sequence reads to detect and quantify one or more somatic mutations at the locus, determining a selection coefficient for the locus, and comparing the selection coefficient with a threshold value to detect positive, neutral, or negative selection at the locus.

Abstract: A predictive cancer model generates a cancer prediction for an individual of interest by analyzing values of one or more types of features that are derived from cfDNA obtained from the individual. Specifically, cfDNA from the individual is sequenced to generate sequence reads using one or more physical assays, examples of which include a small variant sequencing assay, whole genome sequencing assay, and methylation sequencing assay. The sequence reads of the physical assays are processed through corresponding computational analyses to generate each of small variant features, whole genome features, and methylation features. The values of features can be provided to a predictive cancer model that generates a cancer prediction. In some embodiments, the values of different types of features can be separately provided into different predictive models. Each separate predictive model can output a score that can serve as input into an overall model that outputs the cancer prediction.