Notes On The Hardy-Weinberg Principle - CBSE Class 12 Biology
The concept of evolution was understood better with genetics. In the 20thcentury, an English mathematician, Godfrey Hardy, and a German physician, Wilhelm Weinberg, founded the Hardy-Weinberg principle also known as Hardy-Weinberg Equilibrium. Using mathematical modelling based on probability, they stated that allele and genotype frequencies in a population remain in genetic equilibrium from generation to generation unless specific disturbing influences are introduced. Hardy and Weinberg developed a simple equation known as the Hardy-Weinberg Equation to study the genetic equilibrium of a given population. The sum total of all the allelic frequencies is one. Generally, there are two forms of a gene, ie, two alleles for one character. Each of these alleles has an equal chance of getting inherited. Therefore, the frequency of the alleles would be zero point five plus zero point five which is equal to one. Genetic equilibrium serves as a baseline against which we can measure genetic change. However, it is affected by several factors such as gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection. Migration impacts the equilibrium because when a population moves from one place to another, there are changes in the gene frequencies of the old and the new population. When this gene migration takes place many times, it is called gene flow. Genetic drift, which is a change in the relative frequency with which a gene variant occurs in a population due to random sampling and chance. Mutation is another factor that affects the genetic equilibrium. On some occasions, the change in allele frequency due to mutation is so different in the new sample of the population that they become a different species. In this case, the original drifted population becomes the founder and the effect is known as the Founder Effect. Genetic recombination leads to variations in offspring, and if this variation is naturally better selected than the parental genes, it leads to speciation over a period of time. Natural selection also affects genetic equilibrium. Evolution is a slow and sophisticated process. The Hardy-Weinberg Principle helps understand evolution as it provides a baseline to measure the genetic change in a population.

#### Summary

The concept of evolution was understood better with genetics. In the 20thcentury, an English mathematician, Godfrey Hardy, and a German physician, Wilhelm Weinberg, founded the Hardy-Weinberg principle also known as Hardy-Weinberg Equilibrium. Using mathematical modelling based on probability, they stated that allele and genotype frequencies in a population remain in genetic equilibrium from generation to generation unless specific disturbing influences are introduced. Hardy and Weinberg developed a simple equation known as the Hardy-Weinberg Equation to study the genetic equilibrium of a given population. The sum total of all the allelic frequencies is one. Generally, there are two forms of a gene, ie, two alleles for one character. Each of these alleles has an equal chance of getting inherited. Therefore, the frequency of the alleles would be zero point five plus zero point five which is equal to one. Genetic equilibrium serves as a baseline against which we can measure genetic change. However, it is affected by several factors such as gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection. Migration impacts the equilibrium because when a population moves from one place to another, there are changes in the gene frequencies of the old and the new population. When this gene migration takes place many times, it is called gene flow. Genetic drift, which is a change in the relative frequency with which a gene variant occurs in a population due to random sampling and chance. Mutation is another factor that affects the genetic equilibrium. On some occasions, the change in allele frequency due to mutation is so different in the new sample of the population that they become a different species. In this case, the original drifted population becomes the founder and the effect is known as the Founder Effect. Genetic recombination leads to variations in offspring, and if this variation is naturally better selected than the parental genes, it leads to speciation over a period of time. Natural selection also affects genetic equilibrium. Evolution is a slow and sophisticated process. The Hardy-Weinberg Principle helps understand evolution as it provides a baseline to measure the genetic change in a population.

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