Abstract: A system for nucleic acid sequencing is provided. The system comprises a sequencing device configured to expose a tagged polynucleotide comprising a combinatorial barcode sequence and a sample polynucleotide to sequential nucleotide flows, each flow comprising one species of nucleotide and the sequential flows being in a predetermined order based on the species of nucleotide such that exposing of the tagged polynucleotide to the sequential nucleotide flows causes incorporations of nucleotides from the sequential nucleotide flows into the tagged polynucleotide over the barcode sequence The sequencing device is configured to detect a series of signals over the barcode sequence resulting from the incorporations, wherein the predetermined order of nucleotide flows comprises a repetition of a flow order motif that is based on a sequence motif. The system comprises a computing device configured to resolve the detected series of signals to determine the combinatorial barcode sequence.

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: 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 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 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: 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 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: 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: One or more techniques for optimizing cancer classification based on covariate characteristics is disclosed. In a first approach, an analytics system may determine separate cutoff thresholds for positively detecting disease signal for different labels for a covariate characteristic. The system may subdivide training samples based on their labels for the covariate characteristic, to separately determine the cutoff thresholds. In other approaches, the system may train disparate classifiers for each population. The system separates the training samples based on their labels for the covariate characteristic, and separately trains classifiers to generate a signal vector representing an amount of disease signal detected in a sample. The classifiers may be trained on different feature sets as determined based on mutual information gain, genomic region coverage, and healthy activation fraction.

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 method comprises receiving an ensemble of sequencing reads based on measurements from a plurality of microwells of a sensor array; assigning measured values to the ensemble of sequencing reads; calculating model-predicted values utilizing a predictive model of nucleotide incorporations resulting from flows of nucleotide species according to a predetermined order; modifying at least some model-predicted values using a first bias for forward strands and a second bias for reverse strands, the modifying based on variations between model-predicted values for different hypothesized sequences obtained using the predictive model of nucleotide incorporations resulting from the flows of nucleotide species according to the predetermined order; calculating a measurement confidence value for each read in the ensemble of sequencing reads, the confidence value representing variations between the measured values and the modified model-predicted values; and identifying a plurality of reads in the ensemble as corresponding t

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 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.

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 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 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: A simulation system performs microsimulations to model the impact of one or more early cancer detection screenings for a plurality of participants to simulate a randomized controlled trial (RCT). In one instance, the microsimulations are performed using parallel processing techniques. The microsimulation simulates the impact of early detection screenings on individual trajectories of the participants. In particular, while most screening modalities are for single cancer types, the microsimulation herein simulates the effect of a detection model on individual trajectories for participant populations having multiple types of cancer using, for example, multi-cancer early detection (MCED) screenings that are capable of detecting multiple types of cancer.

Abstract: Noise models for processing nucleic acid datasets can stratify processed sequence reads into different read tiers. Each read tier can be defined based on whether a potential variant location is at an overlapping region and/or a complementary region of the sequence reads. A processing system can determine, for each read tier, a stratified sequencing depth at the variant location. The processing system can determine, for reach read tier, one or more noise parameters conditioned on the stratified sequencing depth of the read tier. The noise parameters can be associated with a noise distribution. The processing system can generate an output for each noise model based on the noise parameters conditioned on the stratified sequencing depth. The processing system can combine the output for each stratified noise model to generate a combined result, which can represent a likelihood that an event would be as or more extreme than the observed data.

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 system for nucleic acid sequencing is provided. The system comprises a sequencing device configured to expose a tagged polynucleotide comprising a combinatorial barcode sequence and a sample polynucleotide to sequential nucleotide flows, each flow comprising one species of nucleotide and the sequential flows being in a predetermined order based on the species of nucleotide such that exposing of the tagged polynucleotide to the sequential nucleotide flows causes incorporations of nucleotides from the sequential nucleotide flows into the tagged polynucleotide over the barcode sequence The sequencing device is configured to detect a series of signals over the barcode sequence resulting from the incorporations, wherein the predetermined order of nucleotide flows comprises a repetition of a flow order motif that is based on a sequence motif. The system comprises a computing device configured to resolve the detected series of signals to determine the combinatorial barcode sequence.