Direct cloning by covalent attachment of probe DNA to target DNA.

A novel cloning procedure which makes use of covalent attachment of probe DNA to specific target DNA is reported. We show that specific gene fragments found in complex genomes such as the human genome can be cloned directly from a pool of genomic DNA with very high efficiency. This direct cloning method totally eliminates certain steps in current cloning procedures such as construction of DNA libraries and colony (plaque) hybridization. The resulting process has made cloning methods simpler and more time efficient, while achieving high cloning efficiency due to the stable nature of the probe-target DNA complex through covalent bonding. Most importantly, since clones are directly obtained from a pool of genomic DNA, the isolated clones are considered to be faithful copies of the original genes. This has apparently solved the problem of isolating clones with misincorporated bases or chimeric DNA, both of which are often encountered in cloning processes using PCR or other methods involving in vitro DNA synthesis.