A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandsons from the sons being colour blind ?
A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandsons from the sons being colour blind ?
The correct option is D Nil
In the given question, a colour blind man was found to marry a woman with normal sight who has no history of colour blindness in her family. The colour blind man's genotype is XcY and his wife is XX. This couple would have carrier daughters and normal sons, as colour blindness follows a criss-cross pattern of inheritance. That is from father to daughter and mother to son. In this case, since the mother is normal, daughters are not affected but they are carriers.
We can see that the sons wouldn't carry the affected gene and hence their families will not be affected.
This because the children of all the sons would have the normal genotype XX or XY (assuming that the mother is normal). So the probability of their grandson from the sons being colour blind is nil.
Nil
In the given question, a colour blind man was found to marry a woman with normal sight who has no history of colour blindness in her family. The colour blind man's genotype is XcY and his wife is XX. This couple would have carrier daughters and normal sons, as colour blindness follows a criss-cross pattern of inheritance. That is from father to daughter and mother to son. In this case, since the mother is normal, daughters are not affected but they are carriers.
We can see that the sons wouldn't carry the affected gene and hence their families will not be affected.
This because the children of all the sons would have the normal genotype XX or XY (assuming that the mother is normal). So the probability of their grandson from the sons being colour blind is nil.
