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Modern Genetic Analysis
10. Recombinant DNA Technology
Key Concepts

Recombinant DNA is made by splicing a foreign DNA fragment into a small replicating molecule (such as a bacterial plasmid), which will then amplify that fragment along with itself and result in a molecular clone of the inserted DNA.
Restriction enzymes cut DNA at specific target sites, resulting in defined fragments with sticky ends suitable for insertion into a vector that has been cut open by the same enzyme.
A collection of DNA clones that encompasses the entire genome of an organism is called a genomic library.
An individual DNA clone can be selected from a library by using a specific probe for the DNA or its protein product or by its ability to transform a null mutant.
Different-sized DNA fragments produced by restriction-enzyme digestion can be fractionated because they migrate to different positions on an electrophoretic gel.
RNA or restriction-enzyme-cut DNA molecules that have been fractionated by size in an electrophoretic gel can be probed to detect a specific molecule.
Restriction-enzyme target sites can be mapped, providing useful markers for DNA manipulation.
A gene can be found by testing overlapping clones radiating outward from a linked marker.
After a gene has been cloned, its nucleotide sequence can be determined, and the sequence can be used to study gene function and evolution.
A pair of replication primers spanning a DNA sequence can be used to amplify that sequence for isolation.

© 1999 by W. H. Freeman and Company. All rights reserved.