The term's early usage included any bacterial genetic material that exists extrachromosomally for at least part of its replication cycle, but because that description includes bacterial viruses, the notion of plasmid was refined over time to comprise genetic elements that reproduce autonomously.
O uso inicial do termo incluía calquera material xenético que exista extracromosomicamente para polo menos parte do seu ciclo de replicación, pero como esa descrición inclúía os virus bacterianos, a noción de plásmido foi sendo refinada co tempo para comprender os elementos xenéticos que se reproducen autonomamente.