 Natural bacterial transformation involves the transfer of DNA from a donor bacterium to a recipient bacterium , where both donor and recipient are ordinarily of the same species . Transformation , unlike bacterial conjugation and transduction , depends on numerous bacterial gene products that specifically interact to perform this process . Thus transformation is clearly a bacterial adaptation for DNA transfer . In order for a bacterium to bind , take up and integrate donor DNA into its resident chromosome by homologous recombination , it must first enter a special physiological state termed competence . The RecA / Rad51 / DMC1 gene family plays a central role in homologous recombination during bacterial transformation as it does during eukaryotic meiosis and mitosis . For instance , the RecA protein is essential for transformation in Bacillus subtilis and Streptococcus pneumoniae , and expression of the RecA gene is induced during the development of competence for transformation in these organisms . 
