BIO220H1 Lecture Notes - Lecture 2: Starch, Genetic Hitchhiking, Amylase
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BIO220H1 Full Course Notes
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Caused by selection imposed by each other. Ecology produces selection and genetics provides the material that is transmitted across generations. Humans digest milk using the lactase enzyme. Exception-> people of north european origin and decline in lactase yields the lactose intolerant suite of symptoms. Lactase digestion: african cultures with dairy farming also have distinctive forms of the lactase gene. Strengthens inference that these molecular variants actually affect the phenotype. Independent evolution in different populations supports driving force of natural selection. Independent evolution of the same trait in different groups (populations or species) Allows more confident determination that selection is at work. Differences in the fate of those mutations that change amino acids versus those that do not. Lower genetic variability in regions of the genome that experience selection. More differentiation between populations at selected sites that the rest of the genome". As beneficial mutations fix, they drag along with them nearby mutations = genetic hitchhiking.
