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It has been suggested that new groups of viruses have repeatedly emerged at all stages of evolution, often through the displacement of ancestral structural and genome replication genes. [6] There are three main hypotheses that aim to explain the origins of viruses: [7] Regressive hypothesis
The regressive hypothesis does not explain why even the smallest of cellular parasites do not resemble viruses in any way. The escape or the cellular origin hypothesis does not explain the presence of unique structures in viruses that do not appear in cells.
The viral eukaryogenesis hypothesis points to the cell cycle of eukaryotes, particularly sex and meiosis, as evidence. [6] Little is known about the origins of DNA or reproduction in prokaryotic or eukaryotic cells. It is thus possible that viruses were involved in the creation of Earth's first cells. [8]
Origins of virus responsible for Covid-19 traced to horseshoe bats. Lucinda Cameron. February 9, 2022 at 10:11 AM. The origins of the virus responsible for Covid-19 have been “unambiguously ...
The origins of viruses in the evolutionary history of life are still unclear. ... Regressive hypothesis Viruses may have once been small cells that parasitised larger ...
Viruses may even have multiple origins and different types of viruses may have evolved independently over the history of life. [52] There are different hypotheses for the origins of viruses, for instance an early viral origin from the RNA world or a later viral origin from selfish DNA. [52]
The hunt for the origins of COVID-19 has gone dark in China, the victim of political infighting after a series of stalled and thwarted attempts to find the source of the virus that killed millions ...
[5] [6] In February 2022, the WHO Director General visited China and met the Chinese premier and discussed the need for "stronger collaboration on Covid-19 virus origins, rooted in science and evidence". [7] [8] In July 2023, a review article in The New York Times details information to date about the origins of the Covid-19 virus. [9]