Figure 1.5. Constructing a genomic library.

Figure 1.5

Constructing a genomic library. Genomic DNA and plasmid DNA are cut with EcoRI in preparation for cloning, as in Figure 1.4. (The vector DNA could also be bacteriophage DNA rather than plasmid DNA). In this case, all of the variously sized EcoRI-produced genomic DNA fragments are cloned individually into the EcoRI site of the plasmid, and the recombinant DNA is introduced into E. coli by transformation. Transformed bacteria are selected by growth in the presence of ampicillin, as in Figure 1.4. Since each bacterium can be transformed by only one recombinant plasmid, and since each colony on the agar plate arose from a single transformed bacterium, each colony (or clone) contains amplified plasmid bearing a single genomic EcoRI fragment. Taken together, all the bacterial colonies represent the entire genetic complement of the organism from which the original genomic DNA was isolated. Thus, all of the clones on all of the plates can be thought of as a genomic library, with each individual clone representing one volume.

From: Chapter 1, Molecular Biology

Cover of Holland-Frei Cancer Medicine
Holland-Frei Cancer Medicine. 5th edition.
Bast RC Jr, Kufe DW, Pollock RE, et al., editors.
Hamilton (ON): BC Decker; 2000.
© 2000, BC Decker Inc.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.