During meiosis, which process involves exchanging segments between chromatids of homologous chromosomes?

• A. Crossing over
• B. Mutation
• C. Independent assortment
• D. Translocation

Answer: (A)

Genetic recombination happens when crossing over occurs during prophase I of meiosis, as homologous chromosomes pair up in synapsis. During this stage, segments are exchanged between non-sister chromatids of the homologous chromosomes, forming recombinant chromatids at the points called chiasmata. This exchange creates new combinations of alleles that weren’t present on either parent chromosome, increasing genetic diversity in the gametes.

This process is the best description because it specifically refers to the reciprocal swapping of chromatid segments between homologous chromosomes, which is the mechanism that produces new allele combinations. In contrast, mutation refers to changes in the DNA sequence itself, independent assortment describes how chromosome pairs orient randomly to gametes without exchanging material, and translocation is a chromosomal abnormality where a segment moves to a non-homologous chromosome.