Which process ensures that genetic variations occur during meiosis?

• A. Crossing-over
• B. Mitosis
• C. Stem cell differentiation
• D. DNA repair

Answer: (A)

The process that ensures genetic variations occur during meiosis is crossing-over. This phenomenon takes place during prophase I of meiosis, where homologous chromosomes pair up and exchange segments of genetic material. This exchange reshuffles the alleles between the chromosomes, leading to new combinations of genes in the resulting gametes. As a result, the gametes produced through meiosis have genetic diversity, which is essential for evolution and adaptation in populations.

Mitosis, on the other hand, is a process of cell division that results in two identical daughter cells and does not contribute to genetic variation, as it involves the replication of chromosomes with no exchange of genetic information. Stem cell differentiation pertains to the process where stem cells develop into different cell types, which is also unrelated to the genetic variations that arise during meiosis. DNA repair mechanisms work to fix any damage or errors in the DNA, ensuring the integrity of the genetic material rather than promoting variability.