Question

Frequency of an allele may change in isolated population due to :

• A. Genetic drift
• B. Mutation
• C. Natural selection
• D. Gene flow
• E. All of the above

Answer 1

Answer: (E)

All of the above

• The change in the frequency of a gene that occurs merely by chance and not by selection, in small populations, is called genetic drift or Sewall Wright effect. Genetic drift tends to reduce the amount of genetic variation within the population mainly by removing the alleles with low frequencies.
• The consequences of genetic drift are numerous. It leads to random changes in allele frequencies. Drift causes fixation of alleles through the loss of alleles or genotypes. Drift can lead to the fixation or loss of entire genotypes in clonal (asexual) organisms.
• Its effect is to remove genetic variations from a population of living organisms. In natural populations, there are a number of forces acting. There are forces which add heritable variation to the population, such as mutation and recombination.The main factors change frequencies of alleles for a single genetic locus and therefore cause genetic variation on a small scale. The following causes of microevolution allow violations of the Hardy Weinberg assumption
  1. Genetic Drift
  2. Natural Selection
  3. Gene Flow
  4. Mutation

So the correct option is 'All of the above'.