The origin of plasmids can be traced in ancient times. Probably the first
plasmids were a genetic material somehow excaped from chromosomes (such as
viruses...).
To me plasmids can be considered viruses without a capsid, can be considered
the simplest DNA-based kind of life (whereas viroids are the simplest
RNA-based)
Moreover plasmids behave similar to living organisms, meaning, for example,
that plasmids belonging to the same gruop (-> with the same replication
origin) can't stay together. There are some other behaviours that suggest,
at least, that the genetic information (or maybe just the information) is
life itself and the cells, the organisms are just a sofisticated method in
order to replicate with success... Maybe I'm going mad... maybe not...
