A) Paternal meiosis-I
B) Maternal meiosis-I
C) Paternal meiosis-II
D) Maternal meiosis-II
Correct Answer: B
Solution :
: Downs syndrome is an autosomal aneuploidy, caused by the presence of an extra chromosome number 21. Both the chromosomes of the pair 21 pass into a single egg due to non-disjunction during oogenesis. The non-disjunction is more common in females. The frequency of non- disjunction of chromosome pair 21 increases with mothers age. Usually non-disjunction of chromosomes takes place in meiosis-I.You need to login to perform this action.
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