What is The Royal Disease?

In the 1800s and early 1900s, it was discovered that many of the descendants of Queen Victoria of Great Britain had issues with their blood not clotting. Normally, when you get a bruise or cut, your blood will stick together to form a clot. This closes up the wound and stops you from bleeding. In some people in Queen Victoria’s family, it was very hard for their body to stop bleeding once they started. At times, they might even start bleeding internally (under the skin) for no reason at all.

The chart below shows the descendants of Queen Victoria. Lines connect people who are directly related. In red boxes, we can see the people who had this problem. The half red circles show a person who didn’t have issues with clotting, but had children that had the problem. All of the squares are men and all of the circles are women.

In 1952, this disease was found to be an issue with the enzyme (a type of protein), factor IX. When this protein doesn’t work properly, blood will not be able to stick together to stop bleeding.

1. Factor IX is a , which is formed in living things under the direction of a which is found on a .

Drag the answers below into the grey placeholders above

protein

trait

chromosome

gene

2. Using the model provided, describe the mutation with the enzyme (a type of protein), factor IX. Discuss both how it is passed down and how this mutation affects both men and women. Why is a model like the one provided important to show how hemophilia is passed down from parent to child?

3. The issue we’re seeing with factor IX is a that may be caused by a that causes a change to the organism.

Drag the answers below into the grey placeholders above

mutation

beneficial

neutral

trait

harmful

4. Which statement best explains the relationship between factor IX and a trait of these people?

Enzymes, called blood clots, are only formed when there is a mutation in factor IX.
Factor IX is a gene that is mutated by the trait of blood clotting.
Blood clotting is a trait that’s influenced by a protein called factor IX.
Blood clots influence genes to help prevent the mutation of a protein called factor IX.

5. What relationship can you see between the half-filled sections and the fully filled-in sections?

6. What relationship can be drawn between the fact that only men are affected with this issue and the differences between men’s and women’s chromosomes?

7. Why are there parents in the chart who have children that have problems with their blood clotting, but the parents don’t have the disease?

8. Explain how this phenomenon shows the relationship between proteins and observable traits.

9. One of your classmates makes the following statement about the data:

“ The children who have red box/circle all had one parent with a red box/circle. For those children, the mom gave them all her diseased genes and they did not get any genes from the father.”

Evaluate this statement and, if needed, correct any misconceptions your classmate may have.