Embodiments provided herein relate to methods and compositions for preparing nucleic acid libraries. Some embodiments include preparing libraries from nucleic acids obtained from degraded samples, such as ancient samples and fixed samples.

The present disclosure relates to methods for enrichment or isolation of a long nucleotide fragment comprising a known nucleotide sequence element, i.e. a sequence encoding a conserved active site or domain, the method being applicable i.a. to high throughput screening for DNA fragments containing a known sequence element. The methods herein comprise the steps of forming an emulsion of multiple liquid droplets from a DNA fragment containing liquid sample, specific detection of droplets containing at least one target DNA molecule, physically selecting droplets containing at least one target DNA molecule, and performing a general amplification of the DNA molecules containing at least one target DNA molecules.

The present disclosure relates to methods for enrichment or isolation of a long nucleotide fragment comprising a known nucleotide sequence element, i.e. a sequence encoding a conserved active site or domain, the method being applicable i.a. to high throughput screening for DNA fragments containing a known sequence element. The methods herein comprise the steps of forming an emulsion of multiple liquid droplets from a DNA fragment containing liquid sample, specific detection of droplets containing at least one target DNA molecule, physically selecting droplets containing at least one target DNA molecule, and performing a general amplification of the DNA molecules containing at least one target DNA molecules.

Provided herein are methods, systems, and compositions for determining a base in a polynucleotide. In various aspects, the methods, systems, and compositions presented herein are useful for performing 4-base, 5-base, or 6-base sequencing of polynucleotide molecules, for example, from liquid biopsy samples or wherein the base is a low frequency mutation.

Provided herein are methods, systems, and compositions for determining a base in a polynucleotide. In various aspects, the methods, systems, and compositions presented herein are useful for performing 4-base, 5-base, or 6-base sequencing of polynucleotide molecules, for example, from liquid biopsy samples or wherein the base is a low frequency mutation.

Provided herein are methods for enriching a biological sample for a target nucleic acid, and analyzing the nucleic acid. In some cases, a biological sample is enriched for target nucleic acids associated with a cancer or tumor. In some cases, a biological sample is enriched for target nucleic acids, and the target nucleic acids vary in length. In some cases, one or more probes are used to enrich the biological sample for the target nucleic acid. In some cases, one or more probes hybridize to one or more ends of a target nucleic acid.

Provided herein are methods for enriching a biological sample for a target nucleic acid, and analyzing the nucleic acid. In some cases, a biological sample is enriched for target nucleic acids associated with a cancer or tumor. In some cases, a biological sample is enriched for target nucleic acids, and the target nucleic acids vary in length. In some cases, one or more probes are used to enrich the biological sample for the target nucleic acid. In some cases, one or more probes hybridize to one or more ends of a target nucleic acid.

The present invention relates to novel methods for generating a population of double-stranded polynucleotide molecules from a sample containing at least one polynucleotide.

The present invention relates to novel methods for generating a population of double-stranded polynucleotide molecules from a sample containing at least one polynucleotide.

The present disclosure provides compositions comprising nucleic acid molecules coupled to supports and comprising one or more cleavable or excisable moieties. Methods of enriching and sequencing nucleic acid molecules are also provided.