Which of the following helps explain why increased maternal age is correlated with an increased risk of Down syndrome?
A) mutations accumulate in the germ line in a time-dependent manner
B) meiosis in oocytes is incomplete before fertilization
C) frequency of crossovers increases with gamete age
D) barriers to double fertilization decrease in older ova
E) kinetochore fusion is more common in older women

Question

Quizplus · Accepted Answer

Meiosis in oocytes is arrested in prophase I before birth and does not complete until fertilization. As a woman ages, her oocytes also age, remaining in a suspended state for longer periods. This prolonged arrest can contribute to nondisjunction events during cell division, leading to an increased risk of chromosomal abnormalities such as Down syndrome.

Which of the Following Helps Explain Why Increased Maternal Age