DNA with the 5' end bound to a tyrosine residue in the relaxase. The relaxase then moves toward the 3' end of the strand to unwind the DNA in the plasmid. The other strand of the plasmid, the strand that was not nicked by the relaxase, is a template for further synthesis by DNA polymerase. Once the relaxase reaches the upstream section of the oriT again where there is an inverted repeat, the process is terminated by reuniting the ends of the plasmid and releasing a single-stranded plasmid in the recipient. Applications Genetic engineering Conjugation allows for the transfer of target genes to many recipients, including yeast, mammalian cells, and diatoms. Diatoms could be useful plasmid hosts as they have the potential to autotrophically produce biofuels and other chemicals. There are some methods for genetic transfer for diatoms, but they are slow compared to bacterial conjugation. By designing plasmids for the diatoms P. tricornutum and T. pseudonana based on sequences for yeast and developing a method for conjugation from E. coli to the diatoms, researchers hope to advance genetic manipulation in diatoms. One of the main problems in using bacterial conjugation in genetic engineering is that certain selectable markers on the plasmids generate bacteria that have resistance to antibiotics like ampicillin and kanamycin. Antimicrobial resistance The interaction between the DNA oriT and relaxase enables antimicrobial resistance via horizontal gene transfer (Figure 1). Various oriT regions in plasmid DNA contain inverted repeats onto which relaxase proteins are able bind. Major contributors of drug resistance are mobile genomic islands (MGIs), or segments in DNA that are found in similar strains of bacteria and are factors in diversification of bacteria. MGIs provide resistance to their host cells, and through bacterial conjugation, spread this advantage to other cells. With bacterial cell MGIs having their own oriT sequences and being in close proximity to relaxosome genes, they are very similar to conjugative plasmids that are responsible for the prevalence of drug resistance among bacterial cells. A 2017 study on MGIs revealed that they are able to integrate themselves into the genome of the receiving bacterial cells by themselves via int, a gene that codes for the integrase enzyme. After the oriT of the MGI are processed by the relaxosomes encoded by integrative and conjugative elements (ICE), the MGI are able to enter the genome of the receiver cells and allow for the multiformity of bacteria