During which phase of meiosis does crossing over, a process that increases genetic variation, typically occur?

• A. Metaphase I
• B. Telophase I
• C. Anaphase I
• D. Prophase I

Answer: (D)

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. Recall that meiosis consists of two consecutive divisions: Meiosis I and Meiosis II. Each division has several phases: Prophase, Metaphase, Anaphase, and Telophase.
3. Focus on Meiosis I, where homologous chromosomes are separated. This is the stage where genetic variation is introduced.
4. Identify Prophase I as the phase where homologous chromosomes pair up in a process called synapsis, forming structures known as tetrads.
5. Recognize that during Prophase I, crossing over occurs. This is when homologous chromosomes exchange genetic material, increasing genetic diversity in the resulting gametes.