METHODOLOGY ARTICLE

An inducible recA express iro Background for manipulating large DNA fragments, including bacterial Ogawa et al. BMC Genomics (2015) 16:209 DOI 10.1186/s12864-015-1425-4and it suffers from insert chimerism [3,4].Technology, 4259-B63 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan Full list of author information is available at the end of the articleAs genome analysis progresses, large genome regions including noncoding DNA sequences are drawing much attention. For studies of such regions, techno-logical developments for handling large DNA fragments are essential. Currently, there are several tools available artificial chromosomes (BACs) [1] and yeast artificial chromosomes (YACs) [2]. BACs are based on the F-factor of Escherichia coli and can accommodate genomic DNA inserts of up to 300 kb. BAC clones are easy to manipulate and retrieve because of their plasmid form and the stabil-ity of the cloned DNA. However, YACs can accommodate larger DNA inserts than BACs. Although the cloning capacity of YACs is extremely large, up to 2 Mb, YAC DNA is difficult to purify because of its linear form