68. A New Bacterial Artificial Chromosome (BAC) Vector, a Large-Insert (Average of Over 200 kb) BAC Library of the Human, and an Improved Method of Construction of BAC Libraries 

Sangdun Choi, Yu-Jiun Chen, Mel Simon, and Hiroaki Shizuya 
Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA 
schoi@cco.caltech.edu 

BAC (bacterial artificial chromosome) cloning has served an important role in human and mammalian genomics since its introduction in 1992 by our laboratory. BAC libraries are currently in use or under development for virtually every important genome. The primary reasons why BACs are so useful is that they can stably maintain large DNA inserts (up to 350 kb) in E. coli, and are amenable to virtually all of the sophisticated molecular biology techniques developed for E. coli. We have been constructing BAC libraries of human and mouse in the last several years. Total number of human BAC clones generated is now close to one million. Recently we developed a new BAC vector and an improved method of construction of BAC libraries, and began constructing a series of BAC libraries with much larger insert size (182 - 202 kb) from human and a variety of organisms including Arabidopsis, maize, and rice. The larger insert genomic BAC libraries will provide significant improvement to applications in physical mapping, positional cloning, and DNA sequencing.