The Analysis of One DNA Sequence

Abstract

Before any analysis of a DNA sequence can take place it is first necessary to determine the actual sequence itself, at least as accurately as is reasonably possible. Unfortunately, technical considerations make it impossible to sequence very long pieces of DNA all at once. Instead, many overlapping small pieces are sequenced, each on the order of 500 bases. After this is done the problem arises of assembling these fragments into one long “contig.” One difficulty is that the locations of the fragments within the genome and with respect to each other are not generally known. However, if enough fragments are sequenced so that there will be many overlaps between them, the fragments can be matched up and assembled. This method is called “shotgun sequencing.”