WHAT IS A RETROVIRUS?

Retroviruses are viruses that use the genetic code of their hosts to power their reproduction. Retro Viruses are called Retro viruses because they insert their DNA code into the DNA of their host that allows the virus to use the hosts’ DNA transcription molecules to replicate itself.

Many retroviruses are damaging to their host e.g. the most widely known retrovirus is the human immunodeficiency virus (HIV). However, some retroviruses have been evolved together with their hosts and have provided (by chance) and evolutionary advantage to the host. This is what has happened in the mammal genome as has been prooven by Dr Thomas Spencer and his team at Texas A&M.

The figure below shows how a virus (the red line D) has inserted itself into the host’s DNA so that when the host replicates its DNA or produces mRNA (E), the virus is also replicated (shown as red line C) and uses the cellular machinary to then transcribe its own replications (B&A) that can then infected other cells and their gene sequences.

Figure 1, a cartoon of how a retrovirus replicates (care of: http://www.baclesse.fr)

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