hemophilia?

Question

hemophilia is a sex linked genetic disease in which the normal coagulation of blood does not occure. the mutant allele h is recessive with respect to normal allele H. queen victoria was heterozygous. her husband prince albert was not hemophiliac. what are the expect genotypes of there children ? what are the phenotypes ? what portions of sons and daughters are expected to be hemophiliacs?

Answer 1

Hemophilia is an inherited disorder. It is caused by a defect in the genes that determine how the body makes blood clotting factors VIII and IX. These genes are located on the X chromosomes, which determine whether a baby is a boy or girl.

Chromosomes come in pairs. Females have two X chromosomes, while males have one X and one Y chromosome. A woman is a “carrier” if she has a defective gene for factor VIII or factor IX on one of her X chromosomes. She can pass the defective gene on to her children.

If she has a son, there is a one in two (50 percent) chance that he will have hemophilia.
If she has a daughter, there is a one in two (50 percent) chance that the daughter will be a carrier.

Expected genotypes of the case you presented would be:
Hh or hh


Female Carrier of hemophilia and male haemophiliac

All female offspring would be carriers
All male offspring would be haemophiliacs

Answer 2

The queen was Hh and the prince was Hy. Therefore a girl could have HH or Hh . The prince's H could combine with either the H or the h of the queen. The daughters have a 50% chance of being a carrier.
A boy would be Hy or hy - must get the y from the prince and either the H or the h from the queen. Boys would have a 50% chance of being a hemophiliac.

All possible combinations are: HH, Hy, Hh, hy - The children have a 25% probability of being hemophiliac and a 25% chance of being a carrier.

Answer 3

Haemophilia is a sex linked disease and carried on the X chromosome.
We show this by writing it like this either XH or Xh (with the H's being superscript)
THe different genotypes and phenotypes are:
XHXH = normal female
XHXh = carrier female (does not show condition)
XhXh = affected female
XHy = normal male
XhY= affected male

you can see that it needs 2 copies of Xh for the female to be affected, while only 1 is needed by males...females tend to be carriers of the condition (as they are in many other sex linked conditions) while males suffer more.
AS males ONLY pass the Y (in sperm) to male offsrping only, they cannot pass it to any sons. They can however pass it to females. THe general rule is mother to son to daughter to son.
A female will need both parents to be affected and a carrier to get haemophilia.

So Queen Victoria was XHXh and Prince Albert was XHY

THe cross will be (top line females, bottom line males)
-----XH-----Xh

XH---XHXH--XHXh

Y---XHY----XhY

So out of the females, none will show the condition, but 50% will be carriers.
Males 50% will be normal but 50% will be affected.
If you look at Queen Victorias family tree (pedigree chart) you can see how many children and grandchildren were affected....1 son (out of 4) and 2 daughters (out of 5) were carriers with several of their sons and grandsons affected. See link

Answer 4

For each offspring,there is a fifty percent chance of carrying a defective X chromosome, since the chromosomes from Albert were not defective. So there is a 50% chance for each female to be a carrier, and 50% chance for each male to have haemophilia.

Answer 5

Eat vitamin K.
For more .
http://en.wikipedia.org/wiki/Hemophilia