Strong natural barriers exist against SMGT. However, such barriers are unlikely to be absolutely inviolable. If sperm cells can indeed act as vectors for exogenous DNA, it follows that the genome of sexually reproducing animals may be subject to alteration by exogenous DNA sequences carried by sperm cells. At present there are insufficient data to permit quantification of the rate at which SMGT may occur in nature. Nevertheless, the implications of such ‘natural’ SMGT are significant, and include evolutionary effects on the mammalian genome and pathologies in humans from de novo mutations.
Keywords: Concatemeristion, De novo mutation, Gene knockout, Genome evolution, Homologous recombination, Mammalian genome, Natural SMGT, Random integration, Repetitive sequence, Retrotransposition, Tandem array.