whole genome shot-gun sequencing

whole genome shot-gun sequencing

GENOME sequencing approach, in which the entire genome is fragmented randomly and the fragments cloned and individually end sequenced. The sequences are then placed in their proper order to re-construct the whole genome. This involves the computer technique of'hashing’, which is based on detection of overlapping sequences amongst the fragments, to generate sequence CONTIGS. These are subsequently assembled into the complete genome by closing the gaps between individual sequence contigs (the ‘finishing phase’). The random sequencing approach requires that the total length of sequence generated is several times the length of the genome being studied, in order to ensure that the sequence contigsspan over 99% of the genome sequence. For the sequencing of large genomes, such as the human genome and that of other eukaryotes, this approach thus uses a very large number of individual sequences. Assembly of these sequences is facilitated by reference to a genome map. Celera Genomics used this approach for the human genome sequence, as part of a mixed strategy in combination with data from the IHGSC project (see HUMAN GENOME PROJECT). Compare CLONE METHOD.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005