Retroviruses

A Virus basically consists of a protein capsule with a nucleic acid inside. The nucleic acid could either be DNA or RNA (DNA is what we use for genetic material). If the virus uses DNA, the DNA can directly insert into the host genome and start producing clones of its self.

Retroviruses use RNA which cannot work in a host cell without being translated to DNA then inserted into the host genome. Retroviruses are unique in that they reproduce by transcribing themselves into DNA. Reverse transcriptase, an enzyme within a retrovirus, makes it possible for the retrovirus’ RNA to perform as a template of sorts for the transcription process. Once transcription has taken place, the viral DNA gains access to the DNA of a cell, reproducing along with the cell and its offspring. Within the cell’s offspring, referred to as daughter cells, the viral DNA creates RNA replicas of itself. Finally, the RNA replicas leave the daughter cells after coating themselves with a protein. It just so happens that the process of reverse transcription (RNA to DNA) not very accurate. Many times errors are made which speeds up evolution. Since the life cycle of a virus is very short, millions of copies can be made in a host in a very short amount of time.Because of the rapid evolution of retroviruses, many of the "offspring" will be vastly different than the original. This is why HIV is so difficult to treat, and why a flu vaccine does not work most of the time. They are both retroviruses and evolve faster than science can figure out ways inhibit or treat them.