Abstract: 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.

Abstract: 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.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate. The open substrate may be configured to rotate or otherwise move. The open substrate can comprise an array of individually addressable locations, with analytes immobilized thereto. The substrate may be spatially indexed to identify nucleic acid molecules from one or more sources, and/or sequences thereof, with the respective one or more sources. A solution comprising a plurality of probes may be directed across the array to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via scanning of the substrate while minimizing temperature fluctuations of the substrate or optical aberrations caused by bubbles.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate. The open substrate may be configured to rotate or otherwise move. The open substrate can comprise an array of individually addressable locations, with analytes immobilized thereto. The substrate may be spatially indexed to identify nucleic acid molecules from one or more sources, and/or sequences thereof, with the respective one or more sources. A solution comprising a plurality of probes may be directed across the array to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via scanning of the substrate while minimizing temperature fluctuations of the substrate or optical aberrations caused by bubbles.

Abstract: The present disclosure provides methods and systems for accurate and efficient context-aware base calling of sequences. In an aspect, disclosed herein is a method for sequencing a nucleic acid molecule, comprising: (a) sequencing the nucleic acid molecule to generate a plurality of sequence signals; and (b) determining base calls of the nucleic acid molecule based at least in part on (i) the plurality of sequence signals and (ii) quantified context dependency for at least a portion of the plurality of sequence signals.

Abstract: Described herein are methods of generating a coupled sequencing read pair for a polynucleotide, and methods of analyzing the coupled sequencing read pair. The coupled sequencing read pair can be analyzed to detect polynucleotide variants, including at loci that are not directly sequenced within the coupled sequencing read pair. Other analytical methods can include using coupled sequencing read pairs to construct or validate a consensus sequence. The coupled sequencing read pair may be generated for a polynucleotide by generating sequencing data for a first region by extending a primer using labeled nucleotides; further extending the primer through a second region using nucleotides provided in a second region flow order, wherein primer extension through the second region is faster than primer extension through the first region; and generating sequencing data associated with a sequence of a third region of the polynucleotide by further extending the primer using labeled nucleotides.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate. The open substrate may be configured to rotate or otherwise move. The open substrate can comprise an array of individually addressable locations, with analytes immobilized thereto. The substrate may be spatially indexed to identify nucleic acid molecules from one or more sources, and/or sequences thereof, with the respective one or more sources. A solution comprising a plurality of probes may be directed across the array to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via scanning of the substrate while minimizing temperature fluctuations of the substrate or optical aberrations caused by bubbles.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate. The open substrate may be configured to rotate or otherwise move. The open substrate can comprise an array of individually addressable locations, with analytes immobilized thereto. The substrate may be spatially indexed to identify nucleic acid molecules from one or more sources, and/or sequences thereof, with the respective one or more sources. A solution comprising a plurality of probes may be directed across the array to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via scanning of the substrate while minimizing temperature fluctuations of the substrate or optical aberrations caused by bubbles.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate. The open substrate may be configured to rotate or otherwise move. The open substrate can comprise an array of individually addressable locations, with analytes immobilized thereto. The substrate may be spatially indexed to identify nucleic acid molecules from one or more sources, and/or sequences thereof, with the respective one or more sources. A solution comprising a plurality of probes may be directed across the array to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via scanning of the substrate while minimizing temperature fluctuations of the substrate or optical aberrations caused by bubbles.

Abstract: Provided herein are methods for processing and/or detecting a sample. A method can comprise providing a barrier between a first region and a second region, wherein the first region comprises the sample, wherein the barrier maintains the first region at a first atmosphere that is different than a second atmosphere of the second region, wherein a portion of the barrier comprises a fluid in coherent motion; and using a detector at least partially contained in the first region to detect one or more signals from the sample while the first region is maintained at the first atmosphere that is different than the second atmosphere of the second region. The portion of the barrier comprising fluid may have a pressure lower than the first atmosphere, the second atmosphere, or both.

Abstract: Provided are methods for biological sample processing and analysis. A method can comprise providing a substrate configured to rotate. The substrate can comprise an array having immobilized thereto a biological analyte. A solution comprising a plurality of probes may be directed, via centrifugal force, across the substrate during rotation of the substrate, to couple at least one of the plurality of probes with the biological analyte. A detector can be configured to detect a signal from the at least one probe coupled to the biological analyte, thereby analyzing the biological analyte.

Abstract: Provided are systems and methods for analyte detection and analysis. A system can comprise an open substrate configured to rotate. The open substrate can comprise an array of immobilized analytes. A solution comprising a plurality of probes may be directed, via centrifugal force, across the array during rotation of the substrate, to couple at least one of the plurality of probes with at least one of the analytes to form a bound probe. A detector can be configured to detect a signal from the bound probe via continuous rotational area scanning of the substrate.

Abstract: Provided are systems for biological sample processing and analysis. A system can comprise a substrate configured to rotate. The substrate can comprise an array configured to immobilize a biological analyte. A fluid flow unit comprising a fluid channel can be configured to dispense a solution comprising a plurality of probes. The solution may be directed, via centrifugal force, across the substrate during rotation of the substrate, to couple at least one of the plurality of probes with the biological analyte. A detector in optical communication with the array can be configured to detect one or more signals from the at least one probe coupled to the biological analyte.