Editing Contig (section)

{{short description|Set of overlapping DNA segments that together represent a consensus region of DNA}}
{{about|'''contig''' in DNA sequencing|the '''contig''' defragmentation program|Contig (defragmentation utility)}}[[File:PET contig scaffold.png|thumb|Overlapping reads from paired-end sequencing form contigs; contigs and gaps of known length form scaffolds.]]A '''contig''' (from ''contiguous'') is a set of overlapping DNA segments that together represent a [[Consensus sequence|consensus region of DNA]].<ref name="contig assembly">Gregory, S. ''Contig Assembly''.  Encyclopedia of Life Sciences, 2005.</ref>
In [[Shotgun sequencing#Whole genome shotgun sequencing|bottom-up sequencing]] projects, a contig refers to overlapping sequence data ([[Read (biology)|reads]]);<ref name="textbook">{{cite book |last1=Gibson |first1=Greg |last2=Muse |first2=Spencer V. |title=A Primer of Genome Science |edition=3rd |page=84 |publisher=Sinauer Associates |year=2009 |isbn=978-0-878-93236-8}}</ref> in [[Shotgun sequencing#Hierarchical shotgun sequencing|top-down sequencing]] projects, contig refers to the overlapping clones that form a [[Gene mapping#Physical Mapping|physical map]] of the genome that is used to guide sequencing and [[Sequence assembly|assembly]].<ref name="genome map">Dear, P. H.  ''Genome Mapping''.  Encyclopedia of Life Sciences, 2005. {{doi|10.1038/npg.els.0005353}}.</ref> Contigs can thus refer both to overlapping DNA sequences and to overlapping physical segments (fragments) contained in clones depending on the context.