Haemophilia is also called

What is the cause of haemophilia?

Of a normal couple,half the sons are haemophilic while half the daughters are carriers. The gene is located on $:-$

The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree.

Both husband and wife have normal vision,though their fathers were colourblind and mothers did not have any gene for colour blindness. The probability of their daughter becoming colourblind is

Both male and female have normal vision though their fathers were colour blind,and mothers did not have any gene for colour blindness. The probability of their daughter becoming colour blind is (in $\%$)