Chapter 3 - Chapter 3- The Modern Synthesis Population...

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Chapter 3- The Modern Synthesis Population genetics-the study of what happens to genes undergoing natural selection in populations Genes in Populations Genotypic frequency-the fraction of the population which carries a particular gene Genotypic frequencies must add up to one; frequencies provide information on genetic composition that is independent of time (interested in change over time) *most important forces affecting frequency are sexual reproduction, natural selection, mutation, and genetic drift How Random Mating and Sexual Reproduction Change Phenotypic Frequencies For most genetic loci, mating is random (humans cannot be too picky) 1 st step- determining the effects of sexual reproduction on genotypic frequencies is to calculate the frequency of allele in pool of gametes Gene frequency-frequency of an allele q= freq(aa) + .5(freqAa) = .4 of a, so A must be .6 q= a, p= A 2 nd Calculate the frequencies of all the genotypes among the zygotes Frequency of aa= q sqrd. Frequency of Aa= 2pq AA= p sqrd If no other processes affect the genotypic frequencies, equilibrium will be reached after 1 generation Sexual reproduction-changes distribution of alleles but not frequencies of alleles----NATURAL SELECTION CHANGES ALLELE FREQUENCY How Natural Selection Changes Allele Frequency Hardy-Weinberg stays as long as all genotypes are equally likely to survive and produce gametes
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This note was uploaded on 08/26/2011 for the course ANTHRO 200 taught by Professor Gouzoulesandkonner during the Spring '11 term at Emory.

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Chapter 3 - Chapter 3- The Modern Synthesis Population...

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