A method for assembling nucleic acid sequence fragments is disclosed. The fragments are assembled using information about their relative position inferred by comparison of the fragments against a known sequence of a related nucleic acid (FIG. 3). Additionally, the method localizes fragments to bacterial artificial chromosomes (FIG. 1) and determines relative position of bacterial artificial chromosomes using sequence comparison information (FIG. 6). The method utilizes the information about relative orientation, mutual distance, fragment localization to bacterial artificial chromosomes, and relative position of bacterial artificial chromosomes to constrain the assembly process (FIG. 5), thus resulting in a more accurate assembly requiring fewer sequencing reactions.