EVOLUTION
SOURCES OF VARIATION IN A POPULATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Crossing over
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Random fertilisation
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Separation of sister chromatids
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Independent assortment of chromosomes
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Detailed explanation-1: -Sister chromatids are tightly associated through cohesion, which prevents the separation of sisters before the metaphase-to-anaphase transition (Figure 2). As early as S phase of the cell cycle, cohesion components are present in eukaryotes.
Detailed explanation-2: -Answer and Explanation: B), replication of DNA does not occur in mitosis.
Detailed explanation-3: -Anaphase: During anaphase, the centromere splits, allowing the sister chromatids to separate.
Detailed explanation-4: -A third source of genetic diversity occurs during meiosis II, in which the sister chromatids separate and are randomly distributed to the daughter cells, the gametes. Crossing over in meiosis I leads to non-identical chromatids in meiosis II chromosomes.