Haemophilia X Linked And Punnet Squres
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Haemophilia is a (sex) X linked recessive disease. This means the disease is spread via the X chromosome.
Males having one X chromosome and one Y chromosome are more likely to get haemophilia. An overall probability generalisation for a male to get haemophilia is 50%, it would be that they either have it and show the symptoms or they dont have It at all, it is impossible for a male to have haemophilia but not show symptoms.
This is not the same for females, females have a 2/3 chance of not showing symptoms of haemophilia; being 1/3 chance that theyd be carriers but dont show any symptoms and 1/3 chance that they would not get infected with haemophilia and 1/3 chance that theyd have haemophilia and show symptoms of it.
This is because females have two X chromosomes. A female must have both chromosomes infected with haemophilia for them to show the symptoms, but if one chromosome has haemophilia and the other does not then the chromosomes will balance out and the female will not show symptoms of haemophilia but will be a carrier, and for a female to not have haemophilia at all, both chromosomes must be haemophilia free.
This was just a brief rundown on the statistic probability of getting haemophilia but the probability on contracting Haemophilia in the first place is based on the parents.
The following are the different Haemophiliac combinations that could occur between two people and the probability of their offspring having haemophilia.
H =not infected h = infected with haemophilia
key:
______________
|______dad_____|
____ ______ _____
mum | |girl 1||boy 1|
____| |girl 2||boy 2|
X h X H
X h Y
X h X H
X h Y
100% of girls have haemophilia but shows no traits
100% of boys have haemophilia
X h X h
X h Y
X h X h
X h Y
100% of girls have haemophilia and shows traits
100% of boys have haemophilia
X h X H
X h Y
X H X H
X H Y
50% of girls have haemophilia but shows no traits