Transposable Elements and Rejuvenation of Genome

Transposable elements (TEs) are ubiquitous relicts of ancient viral invasions. Due to the mobility and virus-adopted viability, retroviruses became among the most abundant coding sequences in nature and the prominent force of evolution. TEs can generate new genes or change the expression of neighboring genes. They play a role in rejuvenative totipotency in early embryogenesis and pluripotency of inner cell mass (ICM) in pre-implanted blastocyst. ‘Domesticated’ retrotransposons can be co-opted in conflicts against invasive agents, including alien TEs. Retroviruses have a long history, apparently with periods of activation and recession. Comparative analysis of mammalian species shows that the rate of endogenous retrovirusesEndogenous retroviruses (ERVs) integration in the human genome and the genome of other hominoids experienced a several fold decline during the last 10 million years. Using this ratio of new/old integrations, we observed a significant correlation with species maximum life span. The negative relation (r =  − 0.663; p < 10–5) indicates that long-lived mammals and especially humans exhibit elevated protection against new events of viral integration. Retrovirus can bring new information and co-opt other TEs for utilization of new functionality. Consequently, nearly 70% of the human genome is derived from retroviruses. It provokes a ridiculous question: are humans the mammals with the majority of genes of viral origin, or are they successors of viruses with the minority of mammalian genes? TEs have a controversial nature. They could be usefully symbiotic in embryogenesis, stringently silent in mid-adulthood and loosely controlled and destructive in agingAging. It is believed that cumulative effects of even moderate errors in cellular structure and function can cause genomic instability and less reliable TEs silencing. Is there anything forcing TEs to act destructively in agingAging, or is it the virus-inherited ‘instincts?’ After all, death of a host is counter-productive for TEs too. Without deciphering the role of TEs in embryogenesis and agingAging, discussion of human rejuvenationRejuvenation seems illusive.