AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

RELATIONSHIP BETWEEN GENOTYPE AND GENE FREQUENCIES

• The properties of the population with respect to a single autosomal locus expressed in the Hardy-Weinberg law are:
  • A large random mating population in the absence of migration, mutation and selection is stable with respect to both gene and genotype frequencies.
  • The genotype frequencies in the progeny produced by random mating among the parents are determined solely by the gene frequency among parents.
  • The frequency of homozygotes equals the square of the relevant gene frequency.
  • The frequency of heterozygote equals twice the product of the relevant gene frequencies. Since the frequencies of the genotypes of the homozygotes correspond to the squares of gametic frequencies.
  • Such populations is said to be genetic equilibrium. For a single autosomal locus, the Hardy-Weinberg genotype frequencies are established by one generation of random mating irrespective of the genotype frequencies among parents.
  • For a single locus with two alleles: the maximum frequency of heterozygote will be 0.5. Then p=q=0.5