Question

Sickle-cell anaemia first appeared in Asia, the Middle East, and Africa. The causative allele entered the population of the United States when people were forcibly brought over from Africa prior to the Civil War. In microevolutionary terms, this is a case of ______.

Options

• mutation

• gene flow

• genetic drift

• natural selection

Answer 1

Sickle-cell anaemia first appeared in Asia, the Middle East, and Africa. The causative allele entered the population of the United States when people were forcibly brought over from Africa prior to the Civil War. In microevolutionary terms, this is a case of gene flow.

Explanation:

Sickle-cell anaemia’s causative allele entered the United States population when people were forcibly brought over from Africa. This is a classic example of gene flow, in which alleles are transferred between populations through the migration of individuals. Gene flow introduces new genetic material into a population, leading to microevolutionary changes. It is not due to mutation, genetic drift, or natural selection alone in this context, but rather to the movement of alleles from one population to another.