What occurs during crossing over in meiosis, and why is it significant for genetic variation?

• A. Duplication of chromosomes, resulting in identical genetic material in daughter cells.
• B. Exchange of genetic material between homologous chromosomes, leading to increased genetic variation.
• C. Separation of sister chromatids, ensuring equal distribution of genetic material.
• D. Exchange of genetic material between non-homologous chromosomes, increasing genetic diversity.

Answer: (B)

Verified step by step guidance

1. Understand that meiosis is a type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell.
2. Recognize that crossing over occurs during prophase I of meiosis, where homologous chromosomes pair up closely in a process called synapsis.
3. During crossing over, homologous chromosomes exchange segments of genetic material. This exchange happens at points called chiasmata.
4. This exchange of genetic material between homologous chromosomes results in new combinations of alleles, contributing to genetic variation in the offspring.
5. The significance of crossing over is that it increases genetic diversity within a population, which is crucial for evolution and adaptation to changing environments.