Question

As the chromosome pairs line up during prophase I, some material from the chromatids switch to the exact same position on the other chromosomes. This exchange can happen multiple times on the same pair of chromosomes

Which best describes how crossing over increases genetic diversity?

A.
Crossing over increases genetic diversity because it prevents genetic mutations from occurring within the genes.

B.
Crossing over increases genetic diversity because it ensures that offspring receive the dominant alleles for traits.

C.
Crossing over increases genetic diversity because it results in new combinations of genes on each chromosome.

D.
Crossing over increases genetic diversity because it creates an uneven amount of genetic material on the chromatids.

Answer 1

Correct answer: C

Explanation: During crossing over (prophase I of meiosis) homologous chromosomes exchange corresponding segments, producing recombinant chromosomes with new combinations of alleles. This shuffles parental genes and increases genetic variation among gametes.

Why the others are wrong:
- A: Crossing over does not prevent mutations.
- B: It does not favor dominant alleles; it reshuffles alleles regardless of dominance.
- D: Unequal exchanges (deletions/duplications) can occur but are not the normal mechanism by which crossing over increases typical genetic diversity.