The Genetics of Blood Disorders KEY


1.  If a female is a carrier for hemophilia  X H X h   and is married to a man with hemophilia   X h Y ,  what is the probability that she will have a daughter with hemophilia?

25% of the offspring are daughters daughters with genotype  X h X h

2.  A normal female marries a man who has hemophilia .  (You’ll need to figure out the genotypes).  What percentage of their sons will have hemophilia?  

0 sons will have hemophilia, all inherit the normal allele from mother

man 3.  If a female has hemophilia and is married to a normal man.  
What percentage of her sons will have hemophilia?  

All sons will have hemophilia, all inherit X h from mother and Y from father

What percentage of her daughters will have hemophilia?  

0 daughters with hemophilia, they inherit normal X H allele from fathers

4. A woman with sickle cell anemia is married to a man who is a carrier for the trait.  
(  a  a   x   A  a).  What is the chance of their children having sickle cell anemia?

50% of their children will have sickle cell anemia. This allele is not sex linked, you do not need to include X and Y in the cross or punnett square.

man5.  What is the chance that two people (both being carriers for sickle cell anemia) will have a child with the disease? 25% of the offspring will have sickle cell anemia

6.  Von Willebrand Disease is an autosomal dominant disorder (not located on the sex chromosomes) where blood will not clot properly.  

What would be the two possible genotypes of a person who has the disorder?

DD or Dd will have the disease

If a person is heterozygous for the trait (having the disease) is married to a normal spouse (dd), what is the chance that their children will have the disorder. Dd x dd ; 50% of the children will have the disorder