The present invention provides a method for constructing a next-generation sequencing library for detecting low-frequency mutations, and a kit thereof. The constructing method comprises steps of obtaining blunt-end DNA fragments, obtaining DNA fragments with A-tail at the 3 end, obtaining adapter-added DNA fragments using a specific nucleotide sequence and obtaining amplification products using a specific nucleotide sequence.

Provided are methods for preparing a library of target nucleic acid sequences, as well as compositions and uses therefor. Methods comprise contacting a nucleic acid sample with a plurality of adaptors capable of amplification of one or more target nucleic acid sequences under conditions wherein the target nucleic acid(s) undergo a first amplification; digesting the resulting first amplification products; repairing the digested target amplicons; and amplifying the repaired products in a second amplification, thereby producing a library of target nucleic acid sequence. Each of the plurality of adaptor compositions comprise a handle and a targeted nucleic acid sequence and optionally one or more tag sequences. Provided methods may be carried out in a single, addition only workflow reaction, allowing for rapid production of highly multiplexed targeted libraries, optionally including unique tag sequences. Resulting library compositions are useful for a variety of applications, including sequencing applications.

Methods for the automated template-free synthesis of user-defined sequence controlled biopolymers using microfluidic devices are described. The methods facilitate simultaneous synthesis of up to thousands of uniquely addressed biopolymers from the controlled movement and combination of regents as fluid droplets using microfluidic and EWOD-based systems. In some forms, biopolymers including nucleic acids, peptides, carbohydrates, and lipids are synthesized from step-wise assembly of building blocks based on a user-defined sequence of droplet movements. In some forms, the methods synthesize uniquely addressed nucleic acids of up to 1,000 nucleotides in length. Methods for adding, removing and changing barcodes on biopolymers are also provided. Biopolymers synthesized according to the methods, and libraries and databases thereof are also described. Modified biopolymers, including chemically modified nucleotides and biopolymers conjugated to other molecules are described.

Disclosed herein are methods of constructing a library of target polynucleotides. The present invention finds use in a variety of genomic research and diagnostic applications, including medical, agricultural, food and biodefense fields. Polynucleotides of interest may represent biomarkers of infection (e.g., viral and bacterial), or diseases such as cancer, genetic disorders, and metabolic disorders.

The present invention relates to a method for preparing a library of template polynucleotides and use thereof in methods of solid-phase nucleic acid amplification. More specifically, the invention relates to a method for preparing a library of template polynucleotides that have common sequences at their 5 ends and at their 3 ends.

Provided is a library construction method based on long overhang sequence ligation, a library constructed by the library construction method, for example, a CRISPR library of pair-specific multiplexed guide RNA (gRNA) combinations, and a use of the library. The CRISPR library of pair-specific multiplexed gRNA combinations can be used to simultaneously perturb multiple (e.g., 4) pre-designed targets in CRISPR/Cas9 screening. The CRISPR library of pair-specific multiplexed gRNA combinations can be a powerful tool for studying the combinatorial outcomes from coordinated gene behaviors.

Provided are methods for preparing a library of target nucleic acid sequences, as well as compositions and uses therefor. Methods comprise contacting a nucleic acid sample with a plurality of adaptors capable of amplification of one or more target nucleic acid sequences under conditions wherein the target nucleic acid(s) undergo a first amplification; digesting the resulting first amplification products; repairing the digested target amplicons; and amplifying the repaired products in a second amplification, thereby producing a library of target nucleic acid sequence. Each of the plurality of adaptor compositions comprise a handle and a targeted nucleic acid sequence and optionally one or more tag sequences. Provided methods may be carried out in a single, addition only workflow reaction, allowing for rapid production of highly multiplexed targeted libraries, optionally including unique tag sequences. Resulting library compositions are useful for a variety of applications, including sequencing applications.

The invention relates to a cyclic compound library and a method for making cyclic compounds. The method includes reacting a solid-phase carrier, a molecule containing a photocleavable group, a linking molecule, a building block, and an A-end ring-closure molecule and a B-end ring-closure molecule at the two ends for synthesizing. The method also includes removing the solid-phase carrier using decomposition under light radiation and performing a ring-closure reaction using amino acid residue structures of the A-end ring-closure molecule A and the B-end ring-closure molecule B under the action of a cyclic peptide synthetase.

The invention provides a double-end library tags composition and application thereof in MGI sequencing platform. The double-end library tags composition includes a plurality of 5-end library tags and a plurality of 3-end library tags, the lengths of the plurality of 5-end library tags are all the same, the lengths of the plurality of 3-end library tags are all the same, and in the double-end library tags composition, the occurrences of each base at the same position are also all the same.

Rapid methods, capable of being performed in a single reaction tube, are described herein for constructing libraries for high-throughput polynucleotide sequencing applications, such as next generation sequencing (NGS) applications. Oligonucleotide probes include chemically-active groups at their 5 or 3 ends, or both, to facilitate the cleavage of their 5 or 3 ends, or both, following their hybridization to the single-stranded ends of frayed template fragments. Cleavage of probe ends reveal single-stranded regions at the ends of the hybridized fragments. Adaptors, specific to these ends, are ligated to the hybridized probe/template fragments, and blunt end fragments are ligated to blunt ends of hybridized probe/template fragments, if present, to generate the adaptor-ligated fragments of the library.