Biology 1201A Lecture Notes - Lecture 4: Heterozygote Advantage, Allele Frequency, Zygosity
18 Dec 2017
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Document Summary
Evolutionary forces gene flow, non-random mating, mutation. Gene flow: the incorporation of alleles from one population into another. Must reproduce in the new population - to incorporate alleles. If there is significant and continuous movement, in both directions, between two populations it almost makes these two populations into one big population. Selection against specific phenotypes may not decrease variation in populations. Non-random mating: individuals select mates based on phenotype. Non random mating does not change allele frequencies. Not heterozygote advantage or disadvantage because heterozygotes are still mating and reproducing at the same rates as homozygotes. *non-random mating disrupts the hardy-weinberg equilibrium, but does not cause evolution. Neutral mutations no effect on fitness. Mutations that affect phenotypes are usually harmful to the organism. Homeotic genes regulate the expression of other genes. Mutations in such regulatory genes for development can generate new body shapes.
