Question

What is the Hardy-Weinberg principle for a gene with two alleles in a tetraploid?

Answer 1

In 1908, two scientists, G. N Hardy and W. Weinberg independently discovered Hardy-Weinberg principle, also called as Hardy-Weinberg equilibrium, model, theorem or law. This rule states that:

1. The allelic and genotypic frequencies in a population will remain constant from one generation to next generation and this is known as allelic-frequency equilibrium and genotypic frequency equilibrium.
2. Moreover, allelic and genotypic frequencies do not change due to random mating. Therefore, it is natural equilibrium.

Derivation of the Hardy-Weinberg Law

Let us take a simple example, consider the alleles A and a in a population, whose allele frequencies are p and q. With the concept of random mating each individual has an equal opportunity of mating with another individual in a population.

Where f(A)=p and f(a)=q

(p+q)²= 1

(p²+2pq+q²)=1

Thus, frequency of homozygous A is p²

frequency of homozygous B is q²

And the frequency of heterozygous is 2pq

Similarly, in case of tetraploid following formula has been used,

(p+q)^c= 1

where c is the ploidy, for example with tetraploid (c = 4)

Assumptions for Hardy-Weinberg equilibrium-

Random mating, no natural selection, no mutation, no migration, large population size.