Evolution of Mobile Genetic Elements

The first evolved mobile genetic elements were RNA based viroids.  These circular non protein coding elements gave rise to ribosomal RNA, transfer RNA and messenger RNAs. They probably arose from a GNA world after a Montomorrilate and Iron Sulfur world and assisted by a PAH world.

Viroids gave rise to a Peptide-RNA World  that included RNA dependent polymerase elements such as Leviviridae and Retroviridae.  Subsequent DNA elements arose and diversified into life forms including Plasmids, transposons, and multiple Viral RNA/DNA families.

The network of mobile genetic element evolution can be traced by the capsid, replicative, integrative, and ribozyme structural domains.

Major astrobiological events are equated with the emergence of hybrid mobile genetic element families.

References:

A novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA viruses.

Evolutionary continuum between small RNA and DNA viruses

Origin and evolution of viruses