What does horizontal and vertical gene transfer have to do with symbiosis?

Question

symbiosis - species living in a partnership

Answer 1

Shivani: that's an extremely broad question; it sounds like it's meant to address something in prior reading or presentation. I'm guessing that the underlying idea is that since symbiosis refers to very INTIMATE living relations between two different species, it represents an opportunity for horizontal gene transfer--if E. coli has been living in human guts for thousands of years (and it has) it has basically been bathed in human DNA for that amount of time. So there's a good chance that somewhere along the line, some human DNA was taken up by E. coli. If the transfer was beneficial to E. coli, perhaps its descendants would prosper and that piece of DNA would become part of E. coli as we define it.