Question

State and explain Hardy Weinberg's Principle.

Answer 1

Hardy – Weinberg Principle mathematically explains the occurrence and consistency of gene frequency for a particular gene. The principle states that the allelic frequency remains constant through generations and the gene pool remains constant. This phenomenon is called genetic equilibrium. Also, all the allelic frequencies sum up to 1.
Let us assume, the frequency for the allele X in a population is a and that of the allele x is b.
Thus, the frequency of XX is $a^2$, xx is $b^2$ and Xx is $2ab$. The equation can thus be represented as:
$a^2$ + $b^2$ + $2ab$ = 1
or
$(a+b{)}^2$ = 1
Factors affecting the Hardy-Weinberg principle:

• Mutation
• Genetic drift
• Natural selection
• Genetic recombination
• Gene flow
  

All these factors contribute to the change in gene frequency of a species in an area. If a few individuals from a species migrate to another place, the gene frequency changes again. It decreases from the place from where the individuals migrate and increase in the place they migrate to. If the frequency of the genes is high enough in the newly migrated land to start a new species, the migrated individuals become the founder species, and the effect is called founder effect. Thus, all these mechanisms contribute to the process of evolution.