524
Bacteria share genes all the time. RMS would approve
(sh.itjust.works)
Hey bro, can I have some antibiotic resistance?
Sure bro, but remember that the heavy metal tolerance gene is a dependency.
Shit, I'm on python 2 but hmrA requires python 3.
Rarely used stuff isn't junk DNA. It is still part of the genome, just expressed only under certain conditions (like stress).
Viral sequences do get embedded in host DNA. Some stay mostly inactive, others keep jumping around (and shuffling our genes in usually harmful but occassionally useful combinations) and yet others actually become useful to the host.