All dNA is recombinant dna a Genetic exchange works constantly to blend and rearrange chromosomes, most obviously during meiosis, when homologous chromosomes pair prior to the first nuclear division a During this pairing, genetic exchange between the chromosomes occurs. this exchange, classically termed crossing over, is one of the results of homologous recombination.◼ All DNA is recombinant DNA. ◼ Genetic exchange works constantly to blend and rearrange chromosomes, most obviously during meiosis, when homologous chromosomes pair prior to the first nuclear division. ◼ During this pairing, genetic exchange between the chromosomes occurs. This exchange, classically termed crossing over, is one of the results of homologous recombination