Next-generation sequencing
Genomics · Bioinformatics · Biotechnology
Say it: nekst jen-uh-RAY-shun SEE-kwen-sing
Next-generation sequencing (NGS) is a set of high-throughput methods that read the sequences of millions of short DNA fragments in parallel.
Also: NGS, massively parallel sequencing, high-throughput sequencing, deep sequencing
Definition
What is next-generation sequencing?
Next-generation sequencing, also called massively parallel or high-throughput sequencing, replaced one-reaction-at-a-time Sanger sequencing with machines that read enormous numbers of DNA fragments simultaneously. The DNA is first broken into short pieces and fitted with adapters, short known sequences that let each piece attach to a surface and be copied into a small cluster. The machine then reads every cluster base by base, often by detecting a flash of fluorescence as each labeled nucleotide is added.
A single run produces millions to billions of short reads, usually a few hundred bases or fewer each. Software then aligns the reads to a reference genome or assembles them from scratch, so bioinformatics is part of every NGS project. In wide use since the mid-2000s, these methods have brought the cost of sequencing a human genome down to around a thousand dollars and the time to a day or two. Newer long-read platforms that read single molecules are sometimes called third-generation sequencing.
NGS underlies whole-genome and whole-exome sequencing, cancer gene panels, RNA sequencing, microbiome studies and tracking the spread of pathogens.
Word parts
Where does the term “next-generation sequencing” come from?
- sequenc-
- a following, an orderLatin sequentia, from sequi, to follow
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Terms that go with it
- Sanger sequencingSanger sequencing is a method for reading the order of bases in DNA that uses chain-terminating nucleotides, developed by Frederick Sanger in the 1970s.
- RNA sequencingRNA sequencing (RNA-seq) is a method that uses high-throughput sequencing to identify and count the RNA molecules in a sample.
- GenomeA genome is the complete set of DNA in an organism or cell, including all of its genes and the stretches of DNA between them.
- BioinformaticsBioinformatics is the science of using computers to gather, store, analyze and share biological data, especially DNA, RNA and protein sequences.
- Sequence alignmentSequence alignment is a way of lining up two or more DNA, RNA or protein sequences so that matching positions share a column, showing how similar they are.
- FASTA formatFASTA format is a plain-text format for DNA, RNA or protein sequences in which each record starts with a header line beginning with > followed by the sequence.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Biology 2e, 17.3 Whole-Genome Sequencing
- NCI Dictionary of Cancer Terms: next-generation sequencing
- NCBI MeSH: High-Throughput Nucleotide Sequencing
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