ABSTRACT
The relatively recent development of techniques to isolate and manipulate specific DNA fragments, more or less at will, has led to advances in the ability to selectively alter the genetic make-up of an organism. Unlike random mutagenesis, a simple but largely uncontrollable process with unpredictable results, genetic alteration using recombinant DNA technology is highly selective. This notwithstanding, the isolation of a specific gene and its introduction and expression in a new host are often technically challenging.
