Population genetics

# Population genetics - Anthro 102 Lecture notes 9/29/09...

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Anthro 102 Lecture notes 9/29/09 Population genetics Population genetics -The study of the frequency of alleles, genotypes and phenotypes in a population. Microevolution: changes in the frequency of alleles from one generation to the next. Macroevolution: the change from one species to another Steps in population genetics 1. Measure the allele and genotype frequencies in our population for a specific trait. Ex: figure out the frequencies of the genes for eye color B and b. 2. Figure out what these same frequencies should look like if the population is not evolving at this gene. 3. Compare the actual frequencies with the hypothetical ones. If the numbers are the same the population is not evolving at this gene. Genotype Frequency : Measure of the relative proportions of different genotypes # of individuals with each genotype divided by total # of individuals Allele Frequency : Relative proportions of different alleles # of each allele divided by the total # of alleles Genotype # individuals cc (No curl) 500 Cc (Curl) 200 CC (Curl) 300 Total=1,000 Genotypic frequency : 0.3 CC 0.2 Cc 0.5 cc Phenotypic frequency : 0.5 Curl, 0.5 No curl Allele frequency: (number of particular allele/total number alleles) C = ((2 x 300)+(1 x 200)) = 800 = 0.40 (2 x 1,000) 2,000 c = ((2 x 500)+(1 x 200)) = 1,200 = 0.60 (2 x 1,000) 2,000

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Evolution occurs when gene frequencies change In the absence of evolutionary forces, allele frequencies will remain constant over time The Population will be in
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## This note was uploaded on 12/05/2011 for the course ANTHRO 102 taught by Professor F during the Spring '11 term at CUNY Queens.

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Population genetics - Anthro 102 Lecture notes 9/29/09...

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