Question: A couple is looking forward to having children together. However, they are concerned that the man's mother has a rare genetic condition of slow degenerative muscle weakness, and it has occurred previously in his mother's family. Such phenotype can be caused by different genes. The man does not show the trait, but he is too young to display symptoms. There is no history of this trait in the wife's family and one would assume his wife does not possess an allele. They would like to know the possibility that he may pass the condition to a child. For each of the following possible locations and nature of the allele involved, indicate the probability that any one child of this couple may be affected by the same muscle degeneration condition.