Hardy-Weinberg Equilibrium

The evolutionary processes, or the origin of new species, could not be clearly explained by the theories put forward by Lamarck, Darwin, or Hugo de Vries. Although these theories are vital in the study of evolution, they were unable to explain how variations are passed on to the next generation and how natural selection strengthens the adaptive advantages of organisms. To address these limitations, the concept of Hardy-Weinberg equilibrium was introduced, which is summarized as follows:

The Hardy-Weinberg equilibrium was brought up to establish the conditions in which genetic variation is statically maintained, to serve as a reference point for detecting evolutionary changes. The Hardy–Weinberg Equilibrium is a rule in genetics that tells us how genes behave in a large population.

It says that if nothing changes in a population (no mutation, no migration, no selection, random mating, and a very large size), then:

a) The frequency of alleles (different forms of a gene, like A or a) will stay the same from one generation to the next.

b) The frequency of genotypes (like AA, Aa, or aa) will also remain constant.

Most precisely, Hardy–Weinberg equilibrium concept is like a “genetic balance.” If no outside forces act, the population’s genes stay stable over time.

To understand the concept of this principle, it uses a simple formula:

 p + q = 1

(where p = frequency of dominant allele, q = frequency of recessive allele)

p² + 2pq + q² = 1

(where p² = AA, 2pq = Aa, q² = aa)

Q. What is gene frequency?

Ans- Gene frequency (also known as allele frequency) is the proportion of a specific allele—one form of a gene—at a given locus in the gene pool of a population, relative to the total number of all alleles for that gene present in the population. It is calculated by dividing the number of a particular allele by the total number of alleles for that gene in the population.

Q. What is gene pool?

Ans- A gene pool is the complete set of all genes and their different alleles present within a population of a particular species. It represents the total genetic diversity available in that population and includes all genetic information at every gene locus across all individuals.

Q. What is genetic drift?

Ans- Genetic drift means of exhaustion of genes in a population. Genetic drift is a mechanism of evolution that refers to random changes in the frequencies of alleles (gene variants) in a population from one generation to the next due to chance events.