Multiple additions of new genes or alleles to the new population and their loss from the old population of a particular place due to migration is known as:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Gene flow
Option (1) Gene flow — Correct. It changes allele frequencies in both the old and the new population.
Option (2) Genetic drift — Incorrect. Genetic drift is a change in allele frequency by chance, without migration. It is strongest in small populations.
Option (3) Mutation — Incorrect. A mutation is a change in the DNA itself; it creates a new allele inside the population rather than bringing one in.
Option (4) Natural selection — Incorrect. Natural selection changes allele frequencies because individuals with useful variations survive and reproduce more; no movement of individuals is involved.
NCERT Extract:
Hardy-Weinberg Principle – “… Five factors are known to affect Hardy-Weinberg equilibrium. These are gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection. When migration of a section of population to another place and population occurs, gene frequencies change in the original as well as in the new population. New genes/alleles are added to the new population and these are lost from the old population. There would be a gene flow if this gene migration, happens multiple times.”