Disclosed herein include systems, methods, compositions, and kits for molecular barcoding on the 5′-end of a nucleic acid target. After barcoding a nucleic acid target using an oligonucleotide barcode comprising a target binding region and a molecular label to generate a barcoded nucleic acid molecule, an oligonucleotide comprising a complement of the target binding region can be added to generate a barcoded nucleic acid molecule comprising the target-binding region and the complement of the target-binding region. A stem loop is formed with intra-molecular hybridization of the barcoded nucleic acid molecule, which can be extended to generate an extended barcoded nucleic acid molecule comprising the molecular label and a complement of the molecular label.

Disclosed herein include systems, methods, compositions, and kits for molecular barcoding on the 5′-end of a nucleic acid target. After barcoding a nucleic acid target using an oligonucleotide barcode comprising a target binding region and a molecular label to generate a barcoded nucleic acid molecule, an oligonucleotide comprising a complement of the target binding region can be added to generate a barcoded nucleic acid molecule comprising the target-binding region and the complement of the target-binding region. A stem loop is formed with intra-molecular hybridization of the barcoded nucleic acid molecule, which can be extended to generate an extended barcoded nucleic acid molecule comprising the molecular label and a complement of the molecular label.

The invention provides nucleic acid structures of controlled size and shape, comprised of a plurality of oligonucleotides, and methods for their synthesis. The structures are formed, at least in part, by the self-assembly of single stranded oligonucleotides. The location of each oligonucleotide in the resultant structure is known. Accordingly, the structures may be modified with specificity.

The invention provides nucleic acid structures of controlled size and shape, comprised of a plurality of oligonucleotides, and methods for their synthesis. The structures are formed, at least in part, by the self-assembly of single stranded oligonucleotides. The location of each oligonucleotide in the resultant structure is known. Accordingly, the structures may be modified with specificity.

Compositions, systems, and methods for detecting events are provided. A composition can include a nanopore including a first side, a second side, and an aperture extending through the first and second sides; and a permanent tether including head and tail regions and an elongated body disposed there between. The head region can be anchored to or adjacent to the first or second side of the nanopore. The elongated body including a reporter region can be movable within the aperture responsive to a first event occurring adjacent to the first side of the nanopore. For example, the reporter region is translationally movable toward the first side responsive to the first event, then toward the second side, then toward the first side responsive to a second event. The first event can include adding a first nucleotide to a polynucleotide. The second event can include adding a second nucleotide to the polynucleotide.

Compositions, systems, and methods for detecting events are provided. A composition can include a nanopore including a first side, a second side, and an aperture extending through the first and second sides; and a permanent tether including head and tail regions and an elongated body disposed there between. The head region can be anchored to or adjacent to the first or second side of the nanopore. The elongated body including a reporter region can be movable within the aperture responsive to a first event occurring adjacent to the first side of the nanopore. For example, the reporter region is translationally movable toward the first side responsive to the first event, then toward the second side, then toward the first side responsive to a second event. The first event can include adding a first nucleotide to a polynucleotide. The second event can include adding a second nucleotide to the polynucleotide.

The invention provides compositions and methods for determining whether a subject is predisposed to the disease or condition, or for diagnosing a disease or condition, or for detecting the state of a disease or condition, by detecting the methylation state of the subject's nucleic acids. In addition, the invention provides methods for determining the methylation age of a subject or tissue from a subject or for differentiation between nucleic acids originating from different subjects or tissues. The invention further provides methods for selecting nucleic acid molecules for use in the methods of the invention.

The invention provides compositions and methods for determining whether a subject is predisposed to the disease or condition, or for diagnosing a disease or condition, or for detecting the state of a disease or condition, by detecting the methylation state of the subject's nucleic acids. In addition, the invention provides methods for determining the methylation age of a subject or tissue from a subject or for differentiation between nucleic acids originating from different subjects or tissues. The invention further provides methods for selecting nucleic acid molecules for use in the methods of the invention.

Provided herein, among other things, is a conjugate comprising a polymerase and a nucleoside triphosphate, where the polymerase and the nucleoside triphosphate are covalently linked via a linker that comprises a cleavable linkage. A set of such conjugates, where the conjugates correspond to G, A, T (or U) and C is also provided. Methods for synthesizing a nucleic acid of a defined sequence are also provided. The conjugates can also be used for sequencing applications.

Provided herein, among other things, is a conjugate comprising a polymerase and a nucleoside triphosphate, where the polymerase and the nucleoside triphosphate are covalently linked via a linker that comprises a cleavable linkage. A set of such conjugates, where the conjugates correspond to G, A, T (or U) and C is also provided. Methods for synthesizing a nucleic acid of a defined sequence are also provided. The conjugates can also be used for sequencing applications.