Kazlauskas D, Varsani A, Koonin EV, Krupovic M.

Nat Commun. 2019 Jul 31;10(1):3425. doi:10.1038/s41467-019-11433-0

Multiple origins of prokaryotic and eukaryotic single-stranded DNA viruses from bacterial and archaeal plasmids.

Suggests that papillomaviruses evolved from single-strand DNA viruses, which evolved from bacterial plasmids.