allery**Crossing over** between non-sister chromatids of homologous chromosomes occurs during which phase of meiosis?
AProphase I — pachytene
BMetaphase I
CAnaphase I
DProphase II
Answer & Solution
Correct answer: A. Prophase I — pachytene
Crossing over occurs during the **pachytene** sub-phase of Prophase I, when bivalents (tetrads) have formed and chiasmata develop between non-sister chromatids of homologous chromosomes.
It is the major source of genetic recombination.
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