question_answer

If a boys father has haemophilia and his mother has one gene for haemophilia, what is the chance that the boy will inherit the disease?

A) \[100%\]                             

B) \[75%\]

C) \[50%\]                               

D)

Correct Answer: C

Solution :

Haemophilia is a sex-linked recessive disorder which is transferred by females and expressed by male because the gene present on the X-chromosome and it has double doze of X chromosome in female so in the present problem 25% son will carry the disease. Colourblind                         Carrier Father                   \[\times \]          Mother \[{{X}^{h}}Y\]                                    \[{{X}^{h}}X\]

\[{{X}^{h}}\]	\[{{X}^{h}}\]	\[Y\]
	\[{{X}^{h}}{{X}^{h}}\]