The new one

"...The mRNA is then transcribed in the opposite direction in DNA, which is then incorporated into the chromosome multiplicity of sites, especially those who are genetically transmitted. Retroviral - that's how I named the gene transfer vector negotiated - is the main direction for the development of gene modification. Retroviruses have several distinct advantages over other vectors, especially when the modified gene transfer is the result. The most important advantage offered by the retroviral vector is its ability to transform its unique RNA genome into a double molecule of DNA that is stably integrated into the expected cell genome. This means that retroviral vectors can be used to permanently modify the host cell nuclear genome."