Acquisition of the RAG proteins responsible for generating the diversity of your immune system's B and T cell repertoire (allowing you to develop defenses to mi

Acquisition of the RAG proteins responsible for generating the diversity of your immune system's B and T cell repertoire (allowing you to develop defenses to microbes you have never seen before) may be the result of a herpes virus inserting itself into germ line cells of our ancestors (likely sea lamprey or sea urchin). In short, without viruses we wouldn't be able to defend ourselves against viruses (and other pathogens). Source: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0005778 http://journals.plos.org/plosone/article?id=10.1371/journal.... PDF: https://www.pdf-archive.com/2017/10/06/journal-pone-0005778/ https://www.pdf-archive.com/2017/10/06/journal-pone-0005778/