Population Genetics

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Population Genetics

• The Hardy-Weinberg principle
• Factors that can change allele frequencies

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A. The Hardy-Weinberg Principle

• The frequency of an allele in a population will
  remain constant over time, provided that the
  following conditions are met
• The population is large and randomly breeding
• There are no conditions acting on the population
  to change the allele frequency

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A. The Hardy-Weinberg Principle

• Consider a gene that has two alleles, A and a
• Let p the frequency of A (in a population) q
  the frequency of a
• The frequency of AA p2The frequency of aa
  q2The frequency of Aa 2pqp2 2pq q2 1

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B. Factors That Change Allele Frequencies

• Mutation
• Migration
• Natural selection
• Random genetic drift