Define Founder effect. Give one example.

Hint: Founder effect is the foundation of a new population at a new area due to physical or geographical barriers. The population is reduced to a small size. The genetic composition will be different from the old population.

Complete Answer:
This effect was first outlined by Ernst Mayr in 1942, According to his theory- The loss of genetic variation takes place when a new population is formed from the existing population. These variations can be both genotypic and phenotypic.

Causes of founder effect:
Migration: Few of the population move to a new geographical area. This new population is very small and shows increased sensitivity to genetic drift. They show rise in inbreeding and very low genetic variation.

Consequences: The founder effect is a special case of genetic drift. The new population may have less genetic variation. Through reproduction, new generations are produced. These populations interbreed among themselves which make them more vulnerable to extinction. The founder of the new population affects the genetic makeup in future. The new population can diverge and form many other small colonies in

Example- In case of humans, the reproductive rate is slower. So the genetic drift is not much significant till the population reaches a certain size. Few of the rare alleles can even be lost or can spread in many generations.

Note: According to the founder effect, this drift can lead to evolution of new species. The new population interbreed among themselves over a long period and create an altogether new species which is no longer compatible with the original population.