<p>Disclosed are: a method, when DNA molecules encoding the same protein are ligated to each other, for inhibiting the occurrence of the homologous recombination between or among the ligated genes in a host; and the genes. A polynucleotide having a multiple genes ligated to each other to constitute the same open reading frame, the genes having different nucleotide sequences from each other or one another but encoding the same amino acid sequence, the occurrence of the homologous recombination between or among the genes being inhibited; and a method for producing a recombinant peptide using a DNA vector having the polynucleotide therein.</p>
