Question

Short / Long answer type questions.
Explain the inheritance of hemophilia in the first generation with normal father and carrier mother. Indicate the genotypes and phenotypes of the progeny.

Answer 1

	X	X${}^h$
X	XX (normal daughter)	XX${}^h$ (carrier daughter)
Y	XY (normal son)	X${}^h$Y (haemophilic son)

Haemophilia is an X linked disorder in which blood clotting in the affected individual does not occur.

Normal father (XY) marries carrier mother (XX${}^h$)

50% of daughters will be normal and the other 50% will be carriers. While 50% of sons will be normal and 50% will be hemophilic. Survival rates of hemophilic daughters are very very less.

Phenotypes and genotypes of the progeny are shown in the above cross.