Question

Variation in gene frequencies within populations can occur by chance rather than by natural selection. This is referred to as :

• A.
  Genetic drift
• B.
  Random mating
• C.
  Genetic load
• D.
  Genetic flow

Answer 1

The correct option is A

Genetic drift
Variation in gene frequencies within populations can occur by chance and is called as genetic drift.

Genetic drift is the change in the frequencies of an existing gene in a population due to random sampling of organisms. It may help or harm the organism and affect its survival. The effect of change caused due to change in gene frequencies is dependent on the sample size.

Random mating is a phenomenon in population genetics in which mating is possible between any individuals belonging to the same species.

Genetic load is the reduction in the mean fitness of a population relative to a population composed entirely of individuals having optimal genotypes. It is due to the occurrence of non-beneficial alleles in heterozygous genotype.

Gene flow, also referred to as gene migration, is the introduction from one population of one species to another of genetic material (by interbreeding), thus altering the composition of the gene pool of the receiving population.

So the correct option is "a", Genetic drift".