Lectut btn-202-ppt-l6. cosmids and phagemids

Biotechnology Engineering

1. COSMIDS AND PHAGEMIDS 1 Lecture- 6

2. Cosmids 2

3. Fig : Single cos cosmids Fig : Dual cos cosmids 3

4. in vitro packaging system Cloning strategies used with cosmid vectors 4

5. Another cloning strategy for single cos site vector 5

6. Advantages of cosmids 6

7. Phagemid vectors Phagemid is a filamentous phage-derived vector containing the replication origin of a plasmid Properties Small size High genetic stability Can be used to clone single and double stranded DNA 7

8. Phagemid contains two origins of replication: Plasmid s and phage's Replicates like plasmid producing double-stranded plasmid DNA which has conventional properties Replicates like M13 producing single stranded DNA, packaged and released in presence of a helper phage sequencing work can be done directly, without sub-cloning from the plasmid to phage This process is called DNA rescue 8