This document discusses using family trees to understand inheritance of genetic diseases. It provides examples of family trees showing inheritance of cystic fibrosis and Huntington's disease. Students are asked questions to test their understanding of how to interpret the family trees and the inheritance patterns of recessive versus dominant genetic traits. Family trees allow mapping the inheritance of particular genes to help understand risk of disease in families.

1. Family Trees Aims: To be able to interpret family trees To understand how family trees can help to make important decisions

2. Quick Quiz! In pairs answer the following questions!! 1. What are the symptoms of Huntington's disease? 2. What are the symptoms of Cystic Fibrosis? 3. Is Huntington’s a recessive or a dominant disease? 4. Is Cystic Fibrosis a recessive or a dominant disease? 5.Can someone with either of these disease pass it onto their children?

3. Family trees Family trees can be used to map the inheritance of a particular gene in a family. Why do you think this could be useful?

4. Look at the 2 family trees in front of you… and answer the following questions…. (F) What symbol represents a male with the disease? What symbol represents a female without the disease? Who has the disease in each family? Who could carry the gene for the disease but not have the disease?

5. Look at the 2 family trees in front of you… and answer the following questions…. (H) Who is a carrier in each family? Who has the disease in each family? If Laura marries a carrier what are the chances that their child will have cystic fibrosis? If Emma has a child with a man without a gene for Huntington's what are the chances of their child having Huntington's disorder?

6. The Royal Family

7. Try these!! (F) What is a family tree? Why do you think a family tree could be useful? What disease was present in the Royal family but is no longer? Why are women only carriers of the disease?

8. Try these!! (H) With regards to inherited disease what re the advantages of using family trees? What do family trees allow us to do? What could be the disadvantages to using family trees? Why are women only carriers of the disease?