Question

Without taking into account the likelihood of each type of segregation, what portion of the possible 2:2 segregation products resulting from meiosis in a carrier of a balanced translocation will be normal?

A 1/2
B 1/3
C 1/4
D 1/6
E 1/12

Answer 1

For a carrier of a balanced translocation, while the formation of gametes can vary, one out of the four potential outcomes of gamete formation during meiosis results in normal gametes, which is a 25 percent or 1/4 probability.

Step-by-step explanation:

When considering a carrier of a balanced translocation, the formation of normal gametes during meiosis can be variable. However, without taking into account the likelihood of each type of segregation, and if considering only the 2:2 segregation without any abnormalities, we can imagine four potential outcomes of gamete formation:

• Two normal and two with balanced translocation (normal)
• One normal, one with balanced translocation, and two with unbalanced translocation (abnormal)
• Two with unbalanced translocation and two with the reciprocal unbalanced translocation (both abnormal)
• One with balanced translocation and three with unbalanced translocation (all abnormal)

From these four outcomes, only the first results in normal gametes, which would be 1 out of 4, or 25 percent. Therefore, the proportion of normal gametes is 1/4 or 25 percent. Answer C: 1/4, is the correct choice.