<< Back to glossary index


In next-generation sequencing, a read refers to the DNA sequence from one fragment (a small section of DNA).

Use in clinical context

Most next-generation sequencing technologies fragment the genome prior to sequencing, and each sequenced fragment produces a read. The length of the read and how many are produced will depend on fragment size and the type of technology being used. As the fragments of DNA usually overlap, the reads can be pieced back together to reconstruct the genome. There are other next-generation sequencing methods that do not fragment the genome; these methods are called long-read sequencing as they produce very long reads.

Last updated on 31st May, 2019