Part A The incidence of Down syndrome, also known as trisomy 21, increases with
ID: 23181 • Letter: P
Question
Part AThe incidence of Down syndrome, also known as trisomy 21, increases with increasing maternal age. Which of the following errors most likely produces this condition?
The incidence of Down syndrome, also known as trisomy 21, increases with increasing maternal age. Which of the following errors most likely produces this condition?
Nondisjunction during meiosis II in either the male and female gamete
Nondisjunction during either meiosis I or II in the female gamete
Nondisjunction during either meiosis I or II in the male gamete
Nondisjunction during meiosis I in either the male and female gamete
Part B
Females with only one X chromosome do not develop; this condition is lethal.
Females with only one X chromosome do not develop; this condition is lethal.
True
False
Part C
Which of the following statements about the products produced when nondisjunction occurs during meiosis I is true?
Three products of the second meiotic division have too many chromosomes, while one is missing a chromosome for a particular set.
Both products of the first meiotic division have too many chromosomes.
Both products of the first meiotic division contain dyads representing one chromosome of each homologous pair.
Two products of the second meiotic division have both the maternal and paternal chromosomes of a set and the other two products have none for that set.
Explanation / Answer
A: Nondisjunction during either meiosis I or II in the female gamete B: False C: Two products of the second meiotic division have both the maternal and paternal chromosomes of a set and the other two products have none for that set. D: False