Phage and cosmid vectors Phage A DNA Plasmid Incorporate into virus capsules Restriction cos sites amp site Or g n o 息息 replication Infect E. coli host cells Cleave dNA and plasmid with restriction enzyme. Splice cos DNA into plasmid cos sites F Cosmid vector Select for ampicillin resistance by growing infected cells on medium Linearize cosmid at restriction site containing ampicillin Combine with genomic DNA and ligate Genomic dna strands Surviving cells contain recombinant plasmids which may be cloned. Incorporate into virus capsules