Search results
Results from the WOW.Com Content Network
Viral evolution is a subfield of evolutionary biology and virology that is specifically concerned with the evolution of viruses. [1] [2] Viruses have short generation times, and many—in particular RNA viruses—have relatively high mutation rates (on the order of one point mutation or more per genome per round of replication).
Over 4,800 species of viruses have been described in detail [1] out of the millions in the environment. Their origin is unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. Viruses are made of either two or three parts. All include genes.
The importance of tobacco mosaic virus in the history of viruses cannot be overstated. It was the first virus to be discovered, and the first to be crystallised and its structure shown in detail. The first X-ray diffraction pictures of the crystallised virus were obtained by Bernal and Fankuchen in 1941.
[4] [5] Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, [6]: 4 more than 11,000 of the millions of virus species have been described in detail. [7] [8] The study of viruses is known as virology, a subspeciality of ...
Some viruses can "hide" within a cell, which may mean that they evade the host cell defenses or immune system and may increase the long-term "success" of the virus. This hiding is deemed latency. During this time, the virus does not produce any progeny, it remains inactive until external stimuli—such as light or stress—prompts it to activate.
Gamma phage, an example of virus particles (visualised by electron microscopy) Virology is the scientific study of biological viruses.It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they ...
Viruses may even have multiple origins and different types of viruses may have evolved independently over the history of life. [51] 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. [51]
Viruses enter host cells using a variety of mechanisms, including the endocytic and non-endocytic routes. [4] They can also fuse at the plasma membrane and can spread within the host via fusion or cell-cell fusion. [5] Viruses attach to proteins on the host cell surface known as cellular receptors or attachment factors to aid entry. [6]