[Campbell Biology P.310] Why are the sister chromatids of a chromosome in Metaphase II not g... | Practice Question

Why are the sister chromatids of a chromosome in Metaphase II not genetically identical?

  • A: Because of mutations that occurred during Prophase II.
  • B: Because of crossing over in Meiosis I.
  • C: Because the chromosomes were duplicated incorrectly.
  • D: Because they align randomly at the metaphase plate.

Explanation

The text under Metaphase II explicitly states: 'Because of crossing over in meiosis I, the two sister chromatids of each chromosome are not genetically identical.' Crossing over exchanges segments between non-sister chromatids of a homologous pair.