Question

q2. explain, using an example, how it is possible for a mutation to be harmful in some circumstances but beneficial in others. think /5

Explanation:

A mutation is a change in the DNA sequence. Whether a mutation is harmful or beneficial depends on the environment. For example, sickle - cell anemia is caused by a mutation in the hemoglobin gene. In normal circumstances, having two copies of the sickle - cell allele causes a serious blood disorder (harmful). However, in regions where malaria is prevalent, having one copy of the sickle - cell allele (sickle - cell trait) provides some resistance to malaria (beneficial).

Answer:

A mutation's impact (harmful or beneficial) depends on the environment. For sickle - cell anemia:

• Harmful in normal conditions: Two copies of the sickle - cell allele cause a severe blood disorder.
• Beneficial in malaria - prone areas: One copy (sickle - cell trait) offers malaria resistance.