Biology 1001A Lecture Notes - Lecture 9: Sickle-Cell Disease, Subtypes Of Hiv, Pleiotropy
1 Nov 2015
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Document Summary
Why haven"t we evolved to be healthier: arms races with parasites, optimal virulence depends on ecology of virulence and host, hiv-2 is less easily transmitted between hosts than hiv-1. If one gene has affects on more than one trait, it is pleitropic. Antagonistic pleiotropy has a beneficial affect on one trait or in one context, and a negative effect on another trait or in another context. High levels of sex steroids enhance attractiveness/fertility when young, but increase risk of reproductive cancer. Strength of selection, early vs. late in life, stronger early in life because you are trying to reproduce, no guarantee that you will live to be old. Result: resources channeled into early reproduction, not repair. Closing the book: by altering the ecology of host-parasite interaction, we can make evolution work in our favour. Diseases of civilization: bad for you food, predisposed to diseases, genetic basis for myopia with myopia in the past.
