A method for cloning mixtures of long, synthetic oligodeoxynucleotides

A method is described for cloning synthetic oligodeoxynucleotides, which can theoretically be of any length. The method requires only a single oligodeoxynucleotide strand and a vector with two unique restriction sites, one of which is for an enzyme that generates 3′ protruding ends. A mixture of unpurified oligonucleotides containing a wild-type genetic regulatory sequence of the Escherichia coli gnd gene and two mutations of it was cloned into a plasmid carrying a gnd-lacZ protein fusion. Individual cloned oligonucleotides were readily identified by direct DNA sequencing of plasmid templates. The method is rapid, efficient, and has application to gene synthesis and site-directed mutagenesis.