Question

Question - Predict the types of gametes that are formed if non-disjunction of the Y chromosome occurs in the 2^nd division.

Click on all the different possible gamete types of sperm that could be formed (in terms of the X and Y chromosome, assume that the gamete is normal, having one of all the other chromosome types)

1. X (normal)

2. Y (normal)

3. no X or Y (abnormal)

4. XY (abnormal)

5. YY (abnormal)

6. XX (abnormal)

Answer 1

In case of non disjunction during 2^nd division, gametes are formed with genetic makeup as: n, n, n+1 and n-1. In the given problem, gamates formed due to non-disjunction of Y-chromosome in 2^{nd division will be of types: 1) normal X; 2) normal Y 3) no X or Y abnormal and 4) abnormal XY. Diagrammatically, it is shown below:}

2-dauglitercedis. Pacphase, I AA+ll -S-phase - - Metaphasey Anaphase HAAM lo tan G-phase Telephase I 6-phase Ist Division AA + Autosomes. and division Prophanesi Metapha H-I Telophase Normal X ITAA Anabihase-II ) AA TAA Xy Normal y n+1 Xory L abnormal X Y abnor normal