Hardy-Weinberg Principle - Study Notes

Survived reproduced passed on resistance gene graph

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Unformatted text preview: on resistance gene [Graph] bell-shaped curve shifted to the right o o o Disruptive selection Natural selection favours organism with two extreme forms of a characteristic Balanced polymorphism: equilibrium of non-carriers and carriers of a characteristic caused by natural selection Sickle-cell anaemia o Abnormal Hb makes red blood cells sickle-shaped / stick in capillaries o People homozygous for this recessive allele die before reproducing o People heterozygous for the allele should be at a disadvantage / red blood cells can sickle during exercise / allele should be selected against and rare o Where malaria is found, people heterozygous for sickle-cell have an advantage (resistant) and are likely to survive, reproduce and pass on the allele; people without the allele also have an advantage, because their red cells behave normally o Balanced polymorphism is produced / carrier is heterozygous for sickle cell [GRAPH] Acts against the mode in a range of variation producing a bimodal distribution (two new modes)...
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This document was uploaded on 02/28/2014 for the course BLG 144 at Ryerson.

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