protovirus
Molecular Biol.
noun
1A hypothetical primitive or ancestral virus.
2(In H. M. Temin's terminology) a hypothetical sequence of chromosomal DNA in a somatic cell that can replicate by reverse transcription and give rise by mutation to an oncogenic virus (frequently attributive, especially in protovirus hypothesis, protovirus theory).
Origin
1950s; earliest use found in Language.