Chapter 14, Problem 18P

Genes encoding toxins are often located on plasmids. A recent outbreak has just occurred in which a bacterium that is usually nonpathogenic is producing a toxin. Plasmid DNA can be isolated from this newly pathogenic bacterial strain and separated from the chromosomal DNA. To establish whether the plasmid DNA contains a gene encoding the toxin, you could determine the sequence of the entire plasmid and search for a sequence that looks like other toxin genes previously identified. An easier way exists to determine whether the plasmid DNA carries the gene(s) for the toxin; this strategy does not involve DNA sequence analysis. Describe this easier method.