During which phase of meiosis does crossover occur?

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

Answer: (A)

Verified step by step guidance

1. Understand the process of meiosis, which is a type of cell division that reduces the chromosome number by half, creating four haploid cells. It consists of two stages: Meiosis I and Meiosis II.
2. Learn about the phases of Meiosis I: Prophase I, Metaphase I, Anaphase I, and Telophase I. Each phase has distinct events that contribute to genetic diversity and reduction of chromosome number.
3. Focus on Prophase I, where homologous chromosomes pair up in a process called synapsis. This pairing is crucial for crossover, which is the exchange of genetic material between homologous chromosomes.
4. Recognize that crossover during Prophase I leads to genetic recombination, increasing genetic diversity in the resulting gametes. This is a key feature of sexual reproduction.
5. Review the other phases: Metaphase I involves alignment of homologous pairs at the cell equator, Anaphase I involves separation of homologous chromosomes, and Telophase I concludes the first meiotic division. None of these phases involve crossover.