Question

Case #1 – A couple comes to you and tells you that they have one son, and that he has Duchenne Muscular Dystrophy. They want to have another baby, but aren’t sure if they should try naturally, have in vitro fertilization with embryos that they can select, or use donor sperm. Both parents are healthy and do NOT show traits of this disease. Duchenne Muscular Dystrophy is an x-linked disorder caused by a mutation on one of the x chromosomes. Consider what the chances are for a healthy baby with each of these scenarios and what would you recommend to this couple.

Case #2 – A young woman

Answer 1

Case #2 – A young woman, who was adopted at birth, comes into your office asking you to help her identify her birth father. She already knows that the blood type of her birth mother is A positive. She knows her birth father is one of three men who are willing to help in her search. Your first step is to do a blood test on the daughter. Your results show that she is type AB negative. You make some phone calls and have the three possible fathers come in to give a blood sample. Here are the results:
• Man #1 – O negative
• Man #2 – B negative
• Man #3 – AB positive

From this information, determine what you can conclude about the father.

Answer 2

Case #2
We know the mother has given her child A and r
the father must have B and r too, it is possible for him to be positive or negative, and we can exclude he is not man #1
if only we knew that AB positive is RR, not Rr, we could be sure that he is not the father
and since we can not use genetic tests, (if we could, finger printing was much reliable than ABO blood test) testing MN blood type is the most reliable thing we can do