A new method was developed to rapidly obtain hybrid genes for closely
related proteins. This homolog recombination (E-IR) method is based on
Kunkel site-directed mutagenesis with a set of single-stranded DNA fr
agments generated by Vent polymerase in unidirectional polymerase chai
n reaction (PCR) as mutagenic primers. HR was applied to construct hyb
rid ribonucleases (barnase/binase) and hybrid molecules of human and p
orcine growth hormones.