State and explain any three factors affecting allele frequency in populations.

Five factors are known to affect allele frequency in populations i.e., Hardy-Weinberg equilibrium. These are gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection.

Gene migration or gene flow – it is movement of alleles into a gene pool or out of a gene pool. When this movement of alleles takes place 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. This will lead to a gene flow if this gene migration, happens multiple times.

Genetic drift – If the movement of alleles into a gene pool or out of a gene pool takes place by chance it is called Genetic Drift. This always influences frequencies of alleles and s inversely proportional to the size of the population. It sometimes result into founder effect i.e., when a small group of individuals get isolated from a larger population to form a new population. Genetic drift may result into reduced genetic variation.

Mutation – is the large difference arising suddenly in a population, they are random and occur in all directions.

Natural Selection – is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny. That is nature selects only those traits which help an organism to survive in the changed conditions. Those that are not fit for survival perish in the long run leading to evolution of new species.

Genetic recombination – Production of new offspring with traits which differ from parents is called Genetic recombination.