Write An Essay On The Evolution Of A Virus

Viruses are found wherever there is life and have probably existed since living cells evolved, but the origin of viruses is unclear because they do not form fossils. Instead, researchers have resorted to using molecular techniques to compare DNA of viruses to other organisms. Studies at the molecular level have revealed relationships between viruses infecting organisms from each of the three domains of life and viral proteins that pre-date the divergence of life and thus the last universal common ancestor (Mahy, 2009). Viruses are infectious, microscopic agents. They are not alive by themselves. They require a host cell. Viruses can only replicate inside the living cells of an organism. The virus takes over the cell’s machinery to carry out its own life processes to help it multiply and replicate. The infected cell will produce viral particles instead of the usual products. One of the most recognized and studied is the human immunodeficiency virus (HIV) that leads acquired immunodeficiency syndrome (AIDS). …show more content…
It is caused by HIV. HIV infects cells in the immune system, such as helper T (CD4) cells and macrophages. HIV infection leads to critically low levels of helper T cells which compromises an individual’s cell-mediated immunity. This makes the individual more susceptible to opportunistic infections. HIV originated in primates and is believed to have transferred to humans in a process known as zoonosis. Scientists have identified a type of chimpanzee in West Africa as the source of HIV infection in humans (Sharp,