Biology 1001A Lecture Notes - Lecture 2: Integrase, Thymidine, Smallpox
23 Sep 2016
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Topic: evolution in action: human immunodeficiency virus (hiv) Viruses don"t fit in on this tree of life because it"s a question of debate whether viruses are alive. Viruses are obligate parasites + can"t reproduce alone; they can"t complete their life-cycle w/o exploiting a host because if it can"t obtain a host it will fail to reproduce. Viruses do not metabolize, and do not have cellular membranes. Hiv is a retrovirus (subtype of a virus) Evolutionary history of viruses involves modification of an ancestor that is cellular, a cell-based organism lost its metabolism. Mobile genetic element gained ability to enter/exit cells. Is there one origin or many origins for viruses? (single common ancestral virus or has the virus evolved multiple times) Hiv meets all the conditions for a pandemic disease. It occurs worldwide but not all areas are equally affected, sub-saharan africa is heavily affected.
