The common cold, flu, AIDS, smallpox, yellow fever, Ebola and hepatitis C. What do they have in common? These diseases are viral, in other words they are caused by viruses. Equipped with great powers to adapt to the cells they infect, viruses are also responsible for the emergence of a large number of infectious diseases. Understanding the viral particle’s (virion) rapid processes of evolution constitutes a challenge for numerous research fields, including the recent domain of bioinformatics, a genuine disciplinary intersection in which biologists, computer scientists, mathematicians and physicists work together. In order to better understand the interaction between the virus and the infected cell, or more precisely the process of exchanging genetic material between the two entities responsible for the appearance of new viral or cellular functions, researchers who are specialists in bioinformatics, including the University of Liège biologist Leonor Palmeira, have developed the PhEVER database.
A large number of infectious diseases are triggered by viruses. What is the difference between a virus and another agent which is a pathogenic agent for human beings, such as a bacterium? A bacterium is a cell, whilst the viral particle consists simply of one or more nucleic acid molecules, in the form of DNA or RNA depending on the type of virus, protected by an assemblage of proteins known as a capsid. To multiply the viral particle thus has need of a ‘host’ cell, a cell which it penetrates in order to hijack a part of its machinery, to the benefit of the virus. Another important property of viruses is their ability to combine their genetic programmes between each other, thus giving birth to new strains, and to new diseases. Besides that the exchange of genetic material can also occur between the viral entity and its host cell. In effect when a virus penetrates a cell, it frees its nucleic acid molecules inside it and exchanges with the cell’s genetic material can occur (the RNA of the cytoplasm or the DNA of the nucleus). Certain of these acquisitions can be very beneficial for a virus which receives a gene which allows it to mimic a cell function whilst hijacking it for its own benefit. But how is the exchanged maintained over the course of evolution?