A strategy for sequencing large DNA fragments or entire genomes based on sequencing and ordering small random fragments, typically 20–300 kbp long, obtained by shotgun cloning. It relies primarily on computational power to assemble the numerous and overlapping sequence reads of cloned fragments, obtained by repeated rounds of fragmentation and sequencing, into contiguous sequences, or contigs. Coalescence of the contigs yields a fully assembled whole-genome sequence. By sidestepping the laborious phase of constructing physical maps of clones, shotgun sequencing is potentially faster than other approaches, especially for prokaryote genomes. However, genomes containing large amounts of repetitive DNA and the lack of a reference genome can prove problematical. It was employed by US geneticist Craig Venter’s Celera Genomics company to produce a draft sequence of the human genome, from some 27 million different reads, in just three years and is now widely used to characterized microbial communities using the techniques of metagenomics.