A Medical Application of Evolution
Chimp to Man: The Path of AIDS
Opening paragraph: "Our story begins sometime close to 1921, somewhere between the Sanaga River in Cameroon and the Congo River in the former Belgian Congo. It involves chimps and monkeys, hunters and butchers, “free women” and prostitutes, syringes and plasma-sellers, evil colonial lawmakers and decent colonial doctors with the best of intentions. And a virus that, against all odds, appears to have made it from one ape in the central African jungle to one Haitian bureaucrat leaving Zaire for home and then to a few dozen men in California gay bars before it was even noticed — about 60 years after its journey began."
This article, by Donald G. McNeil, Jr., was published in the New York Times, Science Section, 17 October 2011. Find it at http://www.nytimes.com/2011/10/18/health/18aids.html?_r=1 It nicely summarizes the likely path of the AIDS virus, HIV, from chimpanzees to humans back in the 1920s. The pathway and timing is all based on tracing the evolutionary changes in HIV, a vivid application of viral evolution to medical understanding.
Perhaps the most surprising and fascinating point here is the immense role played by medical techniques in the initial rounds of HIV amplification and spread. It is perhaps more a disease of dirty syringes than of sex.
To help students recognize how the phylogeny of HIV is developed, make use of the excellent treatment at Understanding Evolution: HIV’s not-so-ancient history (with teaching and discussion ideas):
http://evolution.berkeley.edu/evolibrary/news/081101_hivorigins As desired, follow the links and resources to deeper understanding and classroom discussion.
There is also a nice article on the ENSI site that describes how HIV evolution has been used to solve crimes. “Applied Evolution” by James Bull, Ph.D., University of Texas.