Match List-I with List-II:
| List-I | List-II |
|---|---|
| A. Mutation | I. Change in allele frequencies by chance alone |
| B. Gene flow | II. Differences in survival and reproduction among variant individuals |
| C. Natural selection | III. Repeated migration of a section of a population, which changes gene frequencies in both populations |
| D. Genetic drift | IV. Source of new alleles |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-IV, B-III, C-II, D-I
(A) Mutation — this matches (IV) Source of new alleles. A mutation changes the DNA of a gene, so it creates a new allele that was not in the population before. This is the raw material on which the other factors act.
(B) Gene flow — this matches (III) Repeated migration of a section of a population, which changes gene frequencies in both populations. When a group migrates, alleles are added to the new population and lost from the old one. When this migration happens many times, it is called gene flow.
(C) Natural selection — this matches (II) Differences in survival and reproduction among variant individuals. Individuals with heritable variations that help them survive leave more offspring, so their alleles become more common.
(D) Genetic drift — this matches (I) Change in allele frequencies by chance alone. When gene frequencies change by chance, not because of any advantage, the change is genetic drift.
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. If the same change occurs by chance, it is called genetic drift. … Microbial experiments show that pre-existing advantageous mutations when selected will result in observation of new phenotypes. … Natural selection is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny.”