ANTHROP 1AA3 Lecture Notes - Lecture 3: Glutamine, Directional Selection, Valine
30 Sep 2016
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Document Summary
Combination of darwin"s theory of evolution and mendel"s theory of heredity is known as the evolutionary synthesis: Includes the 4 forces of evolution at the molecular level. Mutation is a result of errors in cell division, during replication by dna polymerase. There are three principles to natural selection: there is always natural variation, heritability, differential reproductive success. Positive or directional selection favour one variants of one extreme. Genetic diversity decreases over time in directional selection e. g. moths having a different coating is advantageous/disadvantages. Stabilizing selection acts upon extremes and favors the intermediate. Genetic diversity decreases over time: individuals with high or low values of a trait will not survive. Complex traits are continuous: looking for the average value and variation around this average. E. g. birthweight, babies that are very light do not survive, or babies that are very heavy are not healthy: removal of extremes and favouring intermediate. Favours variants of opposite extremes, both extremes are favoured over intermediates.
