METHODS

摘要

A method of double crossover homologous recombination in a host cell comprising: a first homologous recombination event between a donor DNA molecule comprising a first element of a selectable allele and an acceptor DNA molecule comprising a second element of the selectable allele in the host cell, thereby to form a product of the first homologous recombination event in the host cell; and a second homologous recombination event within the product of the first homologous recombination event, thereby to form a product of the second homologous recombination event in the host cell which confers a selectable phenotype on the host cell, wherein the selectable phenotype arises following and in dependency on the formation of a selectable allele from the first and second elements of the selectable allele.