Abstract: Provided herein are engineered DNA polymerases comprising modifications improving accuracy and processivity of the polymerase including modifications in the Motif A region, optionally, along with additional modifications in the palm and/or exonuclease domains of the polymerase. Also provided are nucleic acids encoding the engineered DNA polymerases comprising modifications in motif A of the polymerase, optionally, with additional modifications. Methods, vectors, kits, and compositions comprising the nucleic acids and compositions, methods and kits comprising the engineered polymerases are also provided.

Abstract: Provided are methods and systems for detecting formation of nucleotide-specific ternary complexes comprising a DNA polymerase, a nucleic acid, and a nucleotide complementary to the templated base of the primed template nucleic acid. The methods and systems facilitate determination of the next correct nucleotide without requiring chemical incorporation of the nucleotide into the primer. This advantageously improves signal-to-noise ratios and increases the quality of results obtainable in a sequencing-by-binding protocol, and enables extended read lengths. These results can even be achieved in procedures employing unlabeled, native nucleotides.

Abstract: A method for identifying target alleles, that includes steps of (a) forming a plurality of stabilized ternary complexes at a plurality of features on an array, wherein the stabilized ternary complexes each has a polymerase, a template nucleic acid having a target allele of a locus, a primer hybridized to the locus, and a next correct nucleotide having a cognate in the locus, wherein either (i) the primer is an allele-specific primer having a 3? nucleotide that is a cognate nucleotide for the target allele, or (ii) the primer is a locus-specific primer and the next correct nucleotide hybridizes to the target allele; and (b) detecting stabilized ternary complexes at the features, thereby identifying the target alleles.

Abstract: Method and composition for identifying cognate nucleotides in a Sequencing By Binding™ procedure, wherein one or more labeled nucleotides are detected in ternary complexes but never incorporated. Labeled nucleotides can be incorporable nucleotides that contact preformed blocked primed template nucleic acids. Alternatively, labeled nucleotides are labeled non-incorporable nucleotides. Labeled nucleotides, including labeled non-incorporable nucleotides, can be detected in ternary complexes in the same reaction mixture that incorporates a reversible terminator nucleotide to create a blocked primed template nucleic acid. Detection of ternary complexes can take place in the presence of a catalytic metal ion.

Abstract: An objective lens is used for DNA sequencing. An example system includes a flow cell, the objective lens, and a camera. Light from the flow cell is imaged by the camera through the objective lens. The objective lens can provide a long working distance; a flat field curvature; a high numerical aperture; and/or a wide field of view.

Abstract: Nucleic acid compositions having nucleotide sequences that do not occur in nature are provided. Also provided are populations of different nucleic acids having universal adapters or universal primer binding sites. Methods of capturing, copying or amplifying nucleic acids of interest using universal adapters, universal primer binding sites and/or universal primers are also provided.

Abstract: An apparatus for evaluating focus, including (a) a stage configured to hold a specimen; and (b) an optical train including a radiation source, calibration optic, objective and detector, the optical train forming a first path wherein radiation from the radiation source is directed to the calibration optic and then a first portion of the radiation is directed to the detector, thereby forming a first image on the detector, wherein a second portion of the radiation follows a second path from the calibration optic then through the objective to the specimen, wherein the optical train forms a third path wherein radiation reflected from the specimen is transmitted through the objective, then to the detector, thereby forming a second image on the detector, and wherein the radiation that forms the first image is astigmatic.

Abstract: An apparatus can include a vessel, a reference surface, a preload, a scan actuator, and a transmitter. The reference surface can form a structural loop with a detector. The preload can be configured to urge the vessel to contact an area on the reference surface. The scan actuator can be configured to slide the vessel along the reference surface in a scan dimension. The transmitter can be configured to direct signal from the vessel to a detector and/or direct energy from an energy source to the vessel, when the vessel is urged by the preload to contact the reference surface.

Abstract: An apparatus can include a vessel, a reference surface, a preload, a scan actuator, and a transmitter. The reference surface can form a structural loop with a detector. The preload can be configured to urge the vessel to contact an area on the reference surface. The scan actuator can be configured to slide the vessel along the reference surface in a scan dimension. The transmitter can be configured to direct signal from the vessel to a detector and/or direct energy from an energy source to the vessel, when the vessel is urged by the preload to contact the reference surface.

Abstract: An analytical system that includes a flow cell, a liquid delivery component, a gas delivery component and a bubble generator component, wherein the liquid delivery component is configured to deliver liquid from one or more reservoirs to the bubble generator component, wherein the gas delivery component is configured to deliver gas from one or more source to the bubble generator component, and wherein the bubble generator component is configured to mix liquids from the liquid delivery component with gas from the gas delivery component to deliver a fluid foam to the inside of the flow cell, wherein the fluid foam includes bubbles of the gas in the liquid.

Abstract: A method for sequencing a population of nucleic acids, which includes (a) binding the population of nucleic acids with a fractionally labeled mixture of nucleotides, thereby forming a fractionally labeled population of nucleic acids, wherein the mixture includes nucleotide cognates for a common base type in the templates, and wherein a fraction of the nucleotide cognates for the common base type in the mixture are exogenously labeled nucleotides that produce a signal that is not produced by other nucleotide cognates for the common base type in the mixture; (b) detecting the signal from the fractionally labeled population of nucleic acids; and (c) repeating (a) and (b) using a second mixture of the fractionally labeled nucleotides, wherein the fraction of the exogenously labeled nucleotides is higher in the second mixture.

Abstract: A reagent cartridge including (a) a support having reservoirs; (b) a main channel within the support, the channel having first and second ends exiting the support; (c) a pump channel that connects to the main channel between the first and second ends; (d) a valve manifold in the support, including (i) a first passage at the first end of the main channel, (ii) a second passage at the second end of the main channel, (iii) a first master valve between the pump channel and the first end of the main channel, (iv) a second master valve between the pump channel and the second end of the main channel, and (v) reservoir valves for regulating flow from individual reservoirs to the main channel. The valves can be normally closed diaphragm valves formed by magnetic pistons attached to an elastomeric sheet that is sandwiched in the support.

Abstract: Provided are nucleic acids encoding engineered polymerases comprising at least one modification in a motif A and/or at least one modification in a motif B of the polymerase and engineered polymerases encoded by the nucleic acids. Also provided are engineered DNA polymerases comprising a variant of SEQ ID NO:1, SEQ ID NO:2, or SEQ ID NO:3, the variant being at least 80% identical to SEQ ID NO:1, SEQ ID NO:2 or SEQ ID NO:3 and comprising an amino acid substitution at one or more positions selected from the group consisting of L408, Y409, P410, R484, A/L485, and I486. Methods, vectors, kits, and compositions comprising the nucleic acids and compositions, methods and kits comprising the engineered polymerases are also provided.

Abstract: Provided are methods and systems for detecting formation of nucleotide-specific ternary complexes comprising a DNA polymerase, a nucleic acid, and a nucleotide complementary to the templated base of the primed template nucleic acid. The methods and systems facilitate determination of the next correct nucleotide without requiring chemical incorporation of the nucleotide into the primer. These results can even be achieved in procedures employing unlabeled, native nucleotides.

Abstract: An analytical system that includes a flow cell, a liquid delivery component, a gas delivery component and a bubble generator component, wherein the liquid delivery component is configured to deliver liquid from one or more reservoirs to the bubble generator component, wherein the gas delivery component is configured to deliver gas from one or more source to the bubble generator component, and wherein the bubble generator component is configured to mix liquids from the liquid delivery component with gas from the gas delivery component to deliver a fluid foam to the inside of the flow cell, wherein the fluid foam includes bubbles of the gas in the liquid.

Abstract: Provided are sequencing-by-binding methods of detecting cognate nucleotides using a crippled DNA polymerizing enzyme that possesses the ability to bind the next correct nucleotide downstream of a primer in a template-dependent fashion, but does not possess the activity needed to promote phosphodiester bond formation. Use of the crippled DNA polymerase permits interrogation of one nucleotide at a time, without incorporation of any nucleotide. Labeled nucleotides, such as fluorescently labeled nucleotides, can be used in conjunction with the crippled DNA polymerase to establish cognate nucleotide identity in a rapid manner.

Abstract: Disclosed herein are finished products, methods, compositions and kits for derivatizing plastic (e.g., “polymer”) surfaces in a manner that renders the surfaces appropriate for various downstream applications. For example, flow cells incorporating modified plastic surfaces provide greatly enhanced stability for retention of attached chemical species such as polypeptides and nucleic acids.

Abstract: Provided herein and methods and apparatuses for sequencing nucleic acids. For example, provided is an analytical detection apparatus, including (a) a stage configured to support a flow cell; (b) a detector configured to observe a detection channel of the flow cell when the flow cell is supported by the stage; (c) a plurality of fluid delivery channels, wherein each of the fluid delivery channels fluidically connects a reservoir to the detection channel of the flow cell; and (d) a first heater configured to heat the plurality of fluid delivery channels.

Abstract: An analytical system that includes a flow cell, a liquid delivery component, a gas delivery component and a bubble generator component, wherein the liquid delivery component is configured to deliver liquid from one or more reservoirs to the bubble generator component, wherein the gas delivery component is configured to deliver gas from one or more source to the bubble generator component, and wherein the bubble generator component is configured to mix liquids from the liquid delivery component with gas from the gas delivery component to deliver a fluid foam to the inside of the flow cell, wherein the fluid foam includes bubbles of the gas in the liquid.

Abstract: An objective lens is used for DNA sequencing. An example system includes a flow cell, the objective lens, and a camera. Light from the flow cell is imaged by the camera through the objective lens. The objective lens can provide a long working distance; a flat field curvature; a high numerical aperture; and/or a wide field of view.