This is my second one, but my last one to ask that i didn't understand

IS it possible for a population's genotype frequencies to change from one generation to the next but for its gene (allele) frequencies to remain constant? Explain by providing example.

Yes, it is possible for a population's genotype frequencies to change from one generation to the next while its gene (allele) frequencies remain constant. This phenomenon is known as the Hardy-Weinberg equilibrium.

The Hardy-Weinberg equilibrium describes a theoretical model of population genetics that assumes certain conditions are met:

1. Random Mating: Individuals in the population mate randomly, with no preference for specific genotypes or phenotypes.

2. Large Population Size: The population is large enough to prevent random genetic drift from significantly altering allele frequencies.

3. No Migration: There is no migration of individuals in or out of the population.

4. No Mutation: There are no new alleles introduced into the population through mutation.

5. No Natural Selection: All genotypes have equal fitness, meaning there is no selective advantage or disadvantage for any particular genotype.

If these conditions are met, the genotype frequencies in the population will reach a stable distribution and remain constant from generation to generation. This means that the proportions of different genotypes in the population will not change.

To provide an example, let's consider a population of rabbits. Suppose there is a gene with two alleles, A and a, responsible for coat color. In the initial generation, the genotype frequencies in the population are as follows:

AA: 0.25
Aa: 0.50
aa: 0.25

Now, if the population meets the conditions of the Hardy-Weinberg equilibrium, the genotype frequencies will remain constant in subsequent generations, even if individuals with different genotypes reproduce.

For instance, in the next generation, the rabbits with different genotypes mate randomly, resulting in the following genotype frequencies:

AA: 0.25
Aa: 0.50
aa: 0.25

As you can see, the genotype frequencies have stayed the same, while the individuals carrying those genotypes may have changed.

This example demonstrates how changes in genotype frequencies can occur within a population while the underlying gene (allele) frequencies remain constant, provided the population satisfies the conditions of the Hardy-Weinberg equilibrium.