How does crossing-over during meiosis contribute to genetic variation?

• A. It ensures that each gamete receives a complete set of chromosomes from one parent only.
• B. It duplicates the genetic material, ensuring each gamete receives an identical set of genes.
• C. It allows for the exchange of genetic material between homologous chromosomes, creating new allele combinations.
• D. It separates sister chromatids, reducing the chromosome number by half.

Answer: (C)

Verified step by step guidance

1. Understand the process of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the production of gametes (sperm and eggs). It consists of two consecutive divisions: meiosis I and meiosis II.
2. Learn about homologous chromosomes: These are pairs of chromosomes, one from each parent, that are similar in shape, size, and genetic content. During meiosis I, homologous chromosomes pair up in a process called synapsis.
3. Explore crossing-over: Crossing-over occurs during prophase I of meiosis I when homologous chromosomes exchange segments of genetic material. This exchange happens at points called chiasmata, leading to new combinations of alleles.
4. Recognize the impact on genetic variation: The exchange of genetic material during crossing-over results in recombinant chromosomes, which have a mix of alleles from both parents. This increases genetic diversity in the offspring.
5. Connect crossing-over to genetic variation: By creating new allele combinations, crossing-over contributes to genetic variation in a population, which is essential for evolution and adaptation.