Question

Mutations are always harmful.

• A. False
• B. True

Answer 1

The correct option is A False

Although generally viewed in a negative light, mutations could either be harmful or beneficial. Conditions like sickle - cell anaemia and haemophilia are well - known examples of harmful mutations. However, mutations could be beneficial too. It is said that humans were originally lactose intolerant. Like most other mammals however, human infants have been able to digest lactose (the milk sugar) because of their ability to produce the enzyme lactase. As they grow older, most humans gradually lose the ability to digest lactose, while some humans continue to be able to digest it through adulthood. It is said that as agricultural practices became widespread, cow’s milk began to be relied upon as a source of food. Gradually, a mutation in the gene coding for the enzyme lactase made individuals “lactose tolerant”. This mutation spread across different human populations, giving them the advantage of being able to digest lactose. Thus, lactose tolerance is an example of a beneficial mutation.