We describe here an in vitro method of redistributing sequence variations between non-identical polynucleotide sequences, by making a heteroduplex polynucleotide from two non-identical polynucleotides; introducing a nick in one strand at or near a base pair mismatch site; remvoing mismatched base(s) from the mismatch site where the nick occurred; and using the opposite stran d as template to replace the removed base(s) with bases that complement base(s ) in the first strand. By this method, information is transferred from one strand to the other at sites of mismatch.
