A phenotypically normal prospective couple seeks genetic counselling because the man knows that he has a translocation of a portion of his chromosome 4, which has been exchanged with a portion of his chromosome 12. Although his translocation is balanced, he and his wife want to know the probability that his sperm will be abnormal. What is your prognosis regarding his sperm?
A) One-quarter will carry the two normal chromosomes, 4 and 12, one-quarter will have only the two translocation chromosomes and no normal chromosomes 4 and 12, and half will have one normal and one translocated chromosome.
B) All will carry the same translocation as the father.
C) None will carry the translocation.
D) Half will be normal, and the rest will have the father's translocation.

Question

Quizplus · Accepted Answer

In a balanced translocation, the individual has all the genetic material needed, but it is rearranged. During meiosis, the chromosomes can segregate in different ways, leading to various combinations in the sperm. One-quarter will have the normal chromosomes, one-quarter will have the translocated chromosomes, and half will have one normal and one translocated chromosome.

A Phenotypically Normal Prospective Couple Seeks Genetic Counselling Because the Man