RNA‑templated diversity generation via reverse transcription and homologous recombination: an evolutionary hypothesis

It is commonly believed that organisms diversify their genomes primarily through point mutations, insertions, and dele-

tions. Here, I propose a complementary mechanism: Diversity Generation by Reverse Transcriptase (DGbyRT), in which

cellular or exogenous RNAs are reverse transcribed into cDNA and integrated into the genome via homology-directed

recombination. This process enables the reuse of modular genetic information—derived from both coding and non-coding

transcripts—thereby biasing variation toward regions already represented in the transcriptome and potentially altering the

statistical distribution of the explored sequence space. DGbyRT draws on mechanisms observed across life, including diver-

sity-generating retroelements, retrotransposons, telomerase, and somatic hypermutation, and may involve endogenous RTs

such as Pol-θ. I hypothesise that transcribed pseudogenes and duplicated sequences may serve as reservoirs for recombinable

modules. DGbyRT may also contribute to somatic-to-germline communication, with reverse-transcribed RNAs crossing the

Weismann barrier to influence heritable change. Inspired by synthetic biology tools such as the AutoDiMe method, DGbyRT

is presented as a context-dependent diversification mechanism whose frequency may be modulated by cellular regulation

of reverse transcriptase activity. As RNA-based technologies advance, understanding natural reverse transcription becomes

increasingly relevant to both evolutionary biology and therapeutic innovation.