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Evolution 2nd Edition

Evolution (2nd Edition)

Book Edition2nd Edition
Author(s)Bergstrom, Dugatkin
PublisherW. W. Norton
Section 7.2: The Hardy-Weinberg Model: A Null Model for Population Genetics
Section 7.3: Natural Selection
Section 7.4: Mutation

Chapter 7, Section 7.2, KEY CONCEPT QUESTION, Exercise 7.1

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The H-W equilibrium is a principle that states that genetic variation in a population does not alter but remains constant from one generation to another in the absence of internal and external disturbing factors.

For a population to be in the H-W equilibrium, the following things should be followed:

  • The mating must be random, with no preferences, so that all the genotypes and allele frequencies remain in equilibrium in the population.
  • Immigration or emigration of individuals from or into a population should not occur, as the equilibrium will be disturbed.
  • Mutations should not occur in the population because they result in the domination of one allele in the population.
  • The size of the population should be large enough that genetic drift does not change the allelic frequency.
  • The survival of a particular trait by natural selection should not occur.

Verified Answer

Five ways that can alter the equilibrium of the population:

  • In a population, the genotype frequencies may alter or change because of gene flow via migration.
  • Assortative mating, where mating occurs within the same phenotype (or same population), can increase the frequency of a particular allele and reduce the frequency of other alleles.
  • The population is not subjected to mutation.
  • The size of the population is infinite.
  • Natural selection does not act on the population and favors a particular trait.
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