Identify the genotype of queen Victoria. (* - gene for disorder)

x*x

The correct answer is Option (2) → x*x

Haemophilia : This sex linked recessive disease, which shows its transmission 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 to this, in an affected individual a simple cut will result in non-stop bleeding. The heterozygous female (carrier) for haemophilia may transmit the disease to 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 the father should be haemophilic (unviable in the later stage of life). The family pedigree of Queen Victoria shows a number of haemophilic descendents as she was a carrier of the disease.

Queen Victoria is believed to have been a carrier of the hemophilia gene, meaning she had one normal X chromosome and one X chromosome carrying the gene for the disorder.

• The correct genotype for a female carrier of hemophilia is X*X, where:
• X represents the normal X chromosome.
• X* represents the X chromosome with the gene for hemophilia.

Since Queen Victoria was a carrier, she did not have the disorder herself but could pass the gene to her offspring, which led to the spread of hemophilia in European royal families.

So, the correct genotype of Queen Victoria is: X*X