Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming a haemophilic extremely rare? Explain.

Explain the pattern of inheritance of haemophilia in humans. Why is th

1.	Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming a haemophilic extremely rare? Explain.
Answer» Haemophilia is a sex-linked (X-chromosome linked) recessive disorder which shows its transmission from unaffected carrier female to some of the male progeny. If the female is a carrier (heterozygous XX^h ), it transmits the disease only to some of her sons but a sufferer (homozygous X^h X^h ) female transmits the disease to all her sons. The possibility of a female becoming haemophilic is extremely rare because to be diseased she has to be homozygous (X^h X^h ) recessive for that trait. As females have 2X chromosomes so there is rare chance of being homozygous recessive.