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.

Text iGenetics by Peter J. Russell

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

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