{"id":10349,"date":"2026-07-03T17:39:42","date_gmt":"2026-07-03T17:39:42","guid":{"rendered":"https:\/\/kapdec.com\/help\/?p=10349"},"modified":"2026-07-03T17:39:42","modified_gmt":"2026-07-03T17:39:42","slug":"hardy-weinberg-equilibrium","status":"publish","type":"post","link":"https:\/\/kapdec.com\/help\/hardy-weinberg-equilibrium\/","title":{"rendered":"Hardy-weinberg Equilibrium"},"content":{"rendered":"
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KAPDEC® | Elite STEM Learning Platform | https:\/\/kapdec.com<\/a><\/p>\n

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Unit: Natural selection<\/strong><\/h2>\n

Chapter: Hardy Weinberg equilibrium<\/strong><\/h3>\n

Reference:<\/em><\/strong> Hardy-Weinberg principle, Importance<\/em><\/p>\n

Learning objectives<\/strong><\/p>\n

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  • To describe the conditions under which allele and genotype frequencies will change in populations.<\/li>\n
  • To explain the impacts on the population if any of the conditions of Hardy-Weinberg are not met.<\/li>\n<\/ul>\n

    Hardy-Weinberg principle<\/strong><\/p>\n

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    • Coined by G. H. Hardy and W. Weinberg, which describes the genetic structure of evolving population.<\/li>\n
    • Mutations introduce new genes into species resulting a change in gene frequencies.<\/li>\n
    • Gene frequency is defined as the frequency with which a particular allele occurs in the population.<\/li>\n<\/ul>\n

      According to Hardy-Weinberg principle allele frequencies in a population are stable and is constant from generation to generation i.e., the gene pool remains constant, called genetic equilibrium.<\/p>\n

      According to this principle a population is only at equilibrium when there is-<\/p>\n

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      • No mutation<\/li>\n
      • No natural or artificial selection<\/li>\n
      • No gene flow (no gene migration)<\/li>\n
      • No genetic drift<\/li>\n
      • No genetic recombination<\/li>\n<\/ul>\n

        Individual frequency for may be named as P, q. etc. in a diploid organism p and q represent the frequency of allele A and a. the frequency of AA individuals in a population is p2<\/sup>. This can be stated in another way, i.e., the probability that an allele A with a frequency of p appears on both the chromosome of a diploid individual is the product of the probabilities i.e., p2<\/sup>. Similarly, of aa is q2<\/sup>, of Aa is 2 pq. Thus, is a binomial expansion of (p+q)2<\/sup>. It is possible to calculate all allele and genotype frequencies using the expressions allele frequency p+q = 1 and genotype frequency p2<\/sup>+2pq+q2<\/sup>=1<\/p>\n

        Importance<\/strong><\/p>\n

        For populations in the Hardy-Weinberg equilibrium, the equation connects allele frequencies to genotype frequencies. This equation allows us to compare a population's genetic structure over time to the expected genetic structure if the population were in Hardy-Weinberg equilibrium.<\/p>\n

        Solved examples<\/strong><\/p>\n

        Example 1<\/strong>. If the frequency of non-tasters of PTC – Paper in a population is 16%, find out the frequency of dominant allele and the percentage of homozygous dominant individuals in the population.<\/p>\n

         Solution 1<\/strong>– The frequency of non-tasters (i.e., homozygous recessive genotype) is 16%,<\/p>\n

        this means that q2<\/sup> = 16% = 16\/100 = 0.16<\/p>\n

        Value of q = 0.16, = 0.4.<\/p>\n

        As p + q = 1, p = (1 – 0.4) = 0.6<\/p>\n

        Frequency of dominant allele (p) will, therefore, be 0.6 or 60%.<\/p>\n

        Now, the frequency of homozygous dominant genotype (p2<\/sup>) = 0.6 × 0.6 = 0.36, or 36%<\/p>\n

        Example 2<\/strong>. Which Hardy-Weinberg factor represents the frequency of heterozygous individuals in a population?<\/p>\n

        a) p2<\/sup>   b)2pq   c) q2<\/sup>   d) p2<\/sup> + 2pq<\/p>\n

        Solution 2<\/strong>. b. The heterozygous individuals in a population are 2pq<\/p>\n

        Summary <\/strong><\/p>\n

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        • Hardy-Weinberg principle is coined by G. H. Hardy and W. Weinberg, which describes the genetic structure of evolving population.<\/li>\n
        • According to Hardy-Weinberg principle allele frequencies in a population are stable and is constant from generation to generation i.e., the gene pool remains constant, called genetic equilibrium.<\/li>\n
        • The factors that affect the Hardy Weinberg principle includes gene flow, genetic drift, mutation, genetic recombination, and natural selection.<\/li>\n<\/ul>\n

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