Question

What causes deviation from Hardy-Weinberg Equilibrium?

Answer 1

The Hardy-Weinberg principle (equilibrium):

1. The principle predicts the frequencies of alleles in a population won’t change from one generation to the next.
2. But only when there is a large population, no mutations, no natural selection, no emigration or immigration.
3. If all these assumptions are met then the allele frequencies of the population will remain stable over time.
4. It is a mathematical model used to calculate the allele frequencies of traits with dominant and recessive alleles.

Causes of Deviation from Equilibrium:

Natural Selection:

1. When natural selection occurs then the variation of traits in the population changes over time
2. The ongoing process in nature where the presence or absence of certain factors in the environment ‘’select’’ which traits or variations within a population are most successful.
3. Most traits are polygenic which is equal to many variations.
4. Without natural selection, the polygenic traits maintain a bell curve.

Genetic Drift:

1. It is a change in allele frequencies due to random events.
2. Genetic drift operates most strongly in small populations.

Gene flow:

1. The flow of genes between populations.
2. Emigration and immigration can cause gene flow between populations and can thus affect gene frequencies.
3. In immigration, genes flow into a population.
4. In Emigration, genes flow out of a population.

Sexual reproduction:

1. In Sexual reproduction, organisms produce large numbers of gametes, so the union of a particular pair is strictly by chance.
2. It has less effect on allele frequencies.

Mutations:

1. Mutations are changes in genes that occur either naturally or influenced by the environment
2. Mutations are changes in the DNA
3. Passed to offspring if occurs in gametes.