Viruses have long been considered to be derailed cellular elements with parasitic propagation: after all, without cell no virus.However, the explosion of recently obtained molecular data of genome and protein sequences creates a completely different image: Viruses contain sequences that are not found anywhere else in the biosphere, which is difficult to reconcile with the idea of a cellular Origin of viruses. Conversely, some cellular sequences of viral origin appear, such as the development of DNA as the main bearer of genetic information. Recent Research makes it plausible that viruses are a crucial link in the evolution of the cell. This idea represents a major step forward in understanding the evolution of cells and also states that viruses continue to survive in addition to cellular life forms. Viruses, which are often regarded purely as enemies of their host, ultimately form a driving force within the evolution.
In The sixties of the last century it was discovered that biomolecules evolve and therefore there must be a molecular evolution. 2 The true explosion of sequence data of the past decades of PROTEINS, RNA and complete taken, has confirmed this image.The sequence data shed new light on the family tree of the cell, the basic form of life on Earth (Figure 1). 3.4
The available sequences include the fact that some cellular mechanisms, such as DNA replication, have evolved more than once in evolution: Thus, DNA replication in bacteria is caused by substantially different enzymes than in eukaryotic cells.
This implies that DNA as a bearer of heredity came to development only after the separation. For other mechanisms, such as that of protein translation, this is not true. Translation proteins are more or less conserved within the 3 Central orders (Bacteria, archaea, Eukarya) and are believed to originate from the same strain: the last common primary cell (see Figure 1). This implies, on the one hand, that there must have been a common primem cell, but that the development of certain life forms after the separation has not stood still.On the other hand, this implies that an alternative hereditary system must exist in the common Primecell, which was based on RNA and that in the long term is replaced by DNA. However, little to nothing is known about the Primecell
Credits 鈧?”written by Jochem M.D. Galama.And this is the link to his article.