What is meant by genetic drift? Explain genetic drift citing the example of founder effect.

• The change in the frequency of a gene that occurs merely by chance in small populations is called genetic drift.
• The alleles with low frequency are removed by chance resulting in fixation of alleles with high frequency.
• Genetic drift is of two types.
  1) Founder Effect.
  2) Bottle-neck effect.

Founder Effect:

•  Founders are a small group of individuals who get separated from their original population and start a new colony in an isolated region. Their offspring are genotypically similar to their founders rather than to their ancestors.
  Example: O-positive blood group in Red-Indian