Home › AP Biology › Biology › Meiosis and Sexual Reproduction › Sister chromatids emerging from meiosis I are no…
Sister chromatids emerging from meiosis I are not perfectly identical because:
AAt least one crossover per chromosome occurs
BReplication copies each strand inaccurately
COne chromatid is always left unreplicated
DEach chromatid is built from a different parent
Answer & Solution
Correct answer: A. At least one crossover per chromosome occurs
1. Sister chromatids are merely duplicates of one of the two homologous chromosomes.
2. That would make them identical if nothing else happened.
3. Instead, they are different because there has always been at least one crossover per chromosome.
4. Crossing over swaps segments between homologues, so each sister ends up carrying a different mixture.
5. Replication itself is faithful, so copying error is not the explanation.
_Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 11 'Meiosis and Sexual Reproduction', sections 11.1-11.2_
Related questions
Sister chromatids are held together at the centromere by which proteins?Comparing life cycles, the dominant stage is diploid in most animals but in fungi it is:The Red Queen hypothesis, offered to explain why sexual reproduction persists, was first pThe four cells produced by meiosis are genetically unique because of independent assortmenMeiosis II is not called a reduction division because the resulting cells still hold:At the end of meiosis I the two cells are already haploid because each pole holds:Interkinesis, the interval between meiosis I and meiosis II, is unusual because it lacks:A spindle fibre that has attached to a kinetochore is called a: