Homework SourseNondisjunction can occur at either the first or second divis
Nondisjunction can occur at either the first or second division of meiosis. An X^w X^w Y female (white eyed) was born from a mating of heterozygous red eyed female X^w X^+ and a hemizygous red eyed (normal) male. This abnormal XwXwY daughter most likely arose from nondisjunction at the ______ meiotic division in the _____.
a) first, mother
b) second, mother
C) first, father
D) second, father
E) more than one of the above could give rise to XXY individuals
Please explain why.
Nondisjunction can occur at either the first or second division of meiosis. An X^w X^w Y female (white eyed) was born from a mating of heterozygous red eyed female X^w X^+ and a hemizygous red eyed (normal) male. This abnormal XwXwY daughter most likely arose from nondisjunction at the ______ meiotic division in the _____.
a) first, mother
b) second, mother
C) first, father
D) second, father
E) more than one of the above could give rise to XXY individuals
Please explain why.
a) first, mother
b) second, mother
C) first, father
D) second, father
E) more than one of the above could give rise to XXY individuals
Please explain why.
Solution
Ans E more than one of the above could give rise to XXY individuals
Meiosis 1 is reductional division so if dysjunction occurs in the fathers chromosome, there will be a diploid gamete of Xw Y which could later fuse with Xw of mother forming XXY individual.
The other possibility is, if the dysjunction occurs in meiosis 2 of mother where her Xw chromosomes do not seperate, then she will form a Xw Xw diploid gamete, which can fuse with Y gamete of father to for XXY.
so options b and c both are possible.
