OBJECTIVE LIFE SCIENCE
GENETICS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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During which phase of meiosis does crossing-over occur?
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Metaphase I
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Prophase I
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Metaphase II
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Prophase II
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Explanation:
Detailed explanation-1: -Although a cell needs to undergo interphase before entering meiosis, interphase is technically not part of meiosis. Crossing over occurs only during prophase I.
Detailed explanation-2: -Prophase I highlights the exchange of DNA between paired chromosomes via a process called homologous recombination and the crossover at chiasmata (singular: chiasma) between non-sister chromatids. Thus, this stage is important to increase genetic variation.
Detailed explanation-3: -Crossing over (recombination) only occurs during Prophase 1 of Meiosis because at this point homologous chromosomes line up at the centre of the cell.
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