Modern Vectors have been constructed to facilitate the cloning of DNA.

• Plasmids such as pBR322 have antibiotic resistance markers for selection and testing for cloning.
• The first problem in cloning is to seperate the transformed cells from non transformed cells.
  This is accomplished by using a vector that has a resistance marker such as ampR or tetR.
• The second problem is seperating religated vector from one with a cloned insert. In pBR322 this is done by cloning in one site (such as tetR) and following cloning checking for tetracycline resistant. If a fragment is cloned in the tetR gene it will be inactive.
  Question: How do you keep from killing the cells you are interested in?

• The addition of a Multiple Cloning Site or polylinker has greatly facilitated the number of restrictgion enzymes that can be used for cloning.
• How can a day of waiting was saved by cloning in the lac z as gene?
• Virus and Bacteraphage can be used as vectors.
  
• Derivatives of Lambda were termed Charons after the ferryman who took the dead over the River Styx(Greek Mythology.
• Cloning using lambda or charons is a good way to make a gene library
• Cosmids combine the advantages of a phage and a plasmid vector.
• BACs and YACs contain the largest inserts.

This web site is provided for instruction in Botany and Zoology 342

by Kenneth G. Wilson,
Professor of Botany
Miami University
wilsonkg@muohio.edu