During which phase of meiosis does crossing over occur?

BIOLOGYSAT 2021

During which phase of meiosis does crossing over occur?

  • A. Anaphase I
  • B. Prophase II
  • C. Anaphase II
  • D. Prophase I

Correct Answer: D. Prophase I

Explanation

Crossing over occurs during Prophase I. During Prophase I, chromatin condenses and homologous chromosomes come together to form a tetrad. At this point, sometimes pieces of the chromatids within the chromosomes break off and exchange DNA. This process is known as crossing over. This cannot occur in Prophase II because there are no homologous chromosomes in this stage, and therefore there isn't any different DNA to exchange.

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