Practice question

Understanding insert capacity hierarchy guides vector selection for genomic projects. M13 filamentous phage accepts less than 4 kb, plasmid pBR322 or pUC accommodates up to 10 kb, lambda phage 15-25 kb, cosmid 35-45 kb, fosmid and P1 70-100 kb, BAC 100-300 kb, PAC similar, YAC up to 2000 kb and MAC beyond 2000 kb. Incremental order demonstrates progressive increase. Among listed orders, M13 smallest, cosmid intermediate, BAC larger and MAC largest represents logically increasing capacity. Recognizing this gradation helps choose appropriate system for cDNA cloning versus genome walking and positional cloning requiring megabase inserts.