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RNA TO DNA. "The transition from the RNA to the DNA world was a major event in the history of life. The invention of DNA required the appearance of enzymatic activities for both synthesis of DNA precursors, retro-transcription of RNA templates and replication of single and double-stranded DNA molecules...DNA can be considered as a modified form of RNA." https://lnkd.in/dNTbYMw View in LinkedIn

ANCIENT LIFE FORMS. "Negatively stranded RNA viruses have genome structures and replication patterns that are dissimilar to all known cell types. As demonstrated by phylogenetic analyses, cellular replicases are related to each other; however, there is no similarity between RNA-viral replicases and those of any known cell types." https://lnkd.in/e-pJFM6 View in LinkedIn

PRE-DNA WORLD. "Since viruses with RNA genomes are the only living beings that use RNA as a storage medium, they are considered to be witnesses of an earlier RNA-world, of a time when DNA did not exist yet." https://lnkd.in/e-pJFM6 View in LinkedIn

MOLECULAR REPLICATION. Prions give credibility to the idea that viruses arose from self-replicating molecules. Molecules interacting with other molecules carrying information sufficient to ensure duplication by whatever means. View in LinkedIn

VIRAL ORIGINS. "Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before, and led to the evolution of, cellular life." http://www.nature.com/scitable/topicpage/the-origins-of-viruses-14398218 View in LinkedIn

UNDER THE BUGSCOPE. "Viruses have evolved highly effective strategies for establishing chronic infection despite the presence of an active host antiviral immune response. Thus, they should be viewed as highly sophisticated molecular machines that have been “studying” us far longer than we have been studying them." http://www.sciencedirect.com/science/article/pii/S0092867409007831 View in LinkedIn

CRITICAL ROLE. "The idea that viruses have played a critical role in the origin of DNA is in line with previous conception that retroviruses were relics of the RNA/DNA world transition." https://lnkd.in/dNTbYMw View in LinkedIn

CANDIDATE GENES APPROACH. "Large numbers of comparative studies have demonstrated that changes in expression patterns of developmental genes are correlated with the evolution of morphological phenotypes. These data underlie the ‘candidate gene’ approach, in which genes that are functionally determined to cause particular phenotypes when mutated are hypothesized to be responsible for similar phenotypic changes during evolution." https://lnkd.in/dD4GcAS View in LinkedIn

LARGER GENOMES. "Replacement of RNA by DNA as genetic material has thus opened the way to the formation of large genomes, a prerequisite for the evolution of modern cells. The above scenario nicely explains why, through Darwinian competition, cell populations with DNA genomes finally eliminated cells with RNA genomes." https://lnkd.in/dNTbYMw View in LinkedIn

TEMPORAL AND SPATIAL CONSIDERATIONS. "Rampant polyploidy in natural populations results in duplicate gene copies that can undergo differential selection and allow for temporal and positional alternations in genetic networks to emerge, conferring novel phenotypes upon which selection may act." https://lnkd.in/dD4GcAS View in LinkedIn