Question

An isolated population of humans with approximately equal numbers of blue-eyed and brown-eyed individuals was decimated by an earthquake. Only a few brown-eyed people remained to form the next generation. This kind of change in the gene pool is called a

• A. Hardy-Weinberg equilibrium
• B. Blocked gene flow
• C. Bottle-neck effect
• D. Gene migration

Answer 1

The correct option is C Bottle-neck effect

When the population is at decline, the number of individuals may reduce to a extent that the small group of population constituting the population becomes isolated and restricted in distribution. These are then exposed to random genetic drift resulting in the fixation of certain genes. Thus, the population re-establishes its former richness. Such reduction in allele frequencies is called a genetic bottle-neck effect which often prevents the species from extinction.

So, the correct answer is 'Bottle-neck effect'.