A deoxyribonucleic acid (DNA) end repair reagent includes: a DNA end repair combinatorial enzyme and a single strand DNA-binding protein (SSB).

Provided are methods of producing size-selected nucleic acid libraries. The methods include contacting a nucleic acid sample and a nucleic acid binding reagent including an affinity tag, under conditions in which nucleic acids of less than a desired length are substantially bound to the nucleic acid binding reagent and nucleic acids of the desired length are substantially not bound to the nucleic acid binding reagent. The conditions include the duration of the contacting, the concentration of the nucleic acid binding reagent, or both. The methods further include separating, using the affinity tag, the nucleic acids of less than the desired length bound to the nucleic acid binding reagent from the nucleic acids of the desired length not bound to the nucleic acid binding reagent, to produce a size-selected nucleic acid library. Compositions and kits that find use, e.g., in practicing the methods of the present disclosure, are also provided.

Disclosed herein is an efficient method of generating a library of variants of a sequence of interest, such as may be used in directed evolution, in one embodiment, the method includes an amplification reaction, e.g. error-prone PCR, to generate double-stranded DNA (dsDNA) variants of a sequence of interest, after which one strand of the dsDNA variants may be selectively degraded to produce single-stranded DNA (ssDNA) variants. The ssDNA variants may be hybridized to ssDNA intermediaries, e.g., uracilated circular ssDNA intermediaries, to form heteroduplex DNA, which may be transformed into cells, such as E. coli cells, yielding a library of variants. This method eliminates the inefficient sub-cloning steps and the need for costly primer sets required by many prior methods.

Provided herein are methods of selective screening. In addition, various targeting proteins and sequences, as well as methods of their use, are also provided.

Compositions and methods are provided for forming a single RNA polynucleotide from a plurality of DNA oligonucleotides in a single reaction chamber using combined reagents in a single step reaction. DNA polymerase, RNA polymerase and single stranded (ss) DNA oligonucleotides are combined where each DNA oligonucleotide has one or more sequence modules, wherein one sequence module in the first ss DNA oligonucleotide is complementary to a sequence module at the 3 end of the second ss DNA oligonucleotide; and wherein a second module on the first ss DNA oligonucleotide is an RNA polymerase promoter sequence; and forming a single RNA polynucleotide, excluding the RNA promoter sequence, derived from the first and second DNA oligonucleotides.

The invention is a novel method of making and using a template for nucleic acid sequencing. The templates include circular and linear templates with symmetric and asymmetric adaptors. The methods include utilizing the templates in an asymmetric fashion.

Methods and systems for sample preparation techniques that allow amplification (e.g., whole genome amplification) and sequencing of chromatin accessible regions of single cells are provided. The methods and systems generally operate by forming or providing partitions (e.g., droplets) including a single biological particle and a single bead comprising a barcoded oligonucleotide. The preparation of barcoded next-generation sequencing libraries prepared from a single cell is facilitated by the transposon-mediated transposition and fragmentation of a target nucleic acid sequence. The methods and systems may be configured to allow the implementation of single-operation or multi-operation chemical and/or biochemical processing within the partitions.

Provided herein are methods of producing molar amounts of nucleic acids in a sample by using fixed molar amounts of primers and amplifying nucleic acids in the sample through a sufficient number of rounds to use all the primer. The methods may be used on a plurality of separate samples to produce samples with molar amounts of nucleic acids that are the same, or substantially the same, or that are related in known molar ratios. Further provided herein are normalized, optionally pooled nucleic acid libraries.

Provided herein are methods of selective screening. In addition, various targeting proteins and sequences, as well as methods of their use, are also provided.

The present invention discloses methods for identification of oligonucleotides by manipulation of the information content a plurality of oligonucleotides. A main object of the methods is the identification of new molecular activity such as new ligands of interest for the development of therapeutics or in the field of nanotechnology.