Biology

This sex linked recessive disease, which shows itstransmission from unaffected carrier female to some of the male progeny has been widely studied. In this disease, a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected. Due tothis, in an affected individual a simple cut will result in non-stop bleeding. The heterozygous female (carrier) for haemophilia may transmit the diseaseto sons. The possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be at least carrier and thefather should be haemophilic (unviable in the later stage of life). The family pedigree of Queen Victoria shows a number of haemophilic descendentsas she was a carrier of the disease.