An Evolutionary Hypothesis on the Persistence of Non-Coding DNA in Complex Genomes: The Passive Selfish DNA Model

Non-coding DNA constitutes the vast majority of eukaryotic genomes, yet its evolutionary role remains largely unresolved. This manuscript proposes a theoretical model in which non-coding DNA persists not due to functional utility, but as "passive selfish DNA"—elements that replicate by coexisting with coding sequences in vital genomes. Drawing analogies with endogenous retroviruses and vertically transmitted transposons, this perspective reframes the issue of genomic persistence in terms of replicative neutrality and genomic compatibility rather than function. The model suggests new directions for investigating genome architecture and evolutionary neutrality.