Principle Of Inheritance And Variation Question 407
Question: One child is haemophilic (sex-linked trait), while its fraternal twin brother is normal. Which one of the following informations is most appropriate?
Options:
A) The mother must have been heterozygous.
B) The child is a monozygotic twin.
C) The other child is a female and the father is haemophilic.
D) The haemophilic child is a male.
Show Answer
Answer:
Correct Answer: A
Solution:
[a] The mother must have been a haemophilic carrier (X"X).
One of the twins would have inherited the normal X chromosome and the other would have received the X chromosome carrying the gene for haemophilia.
BETA
