1. family and parenting
2. children

Name: ___________________________________
Hr: _____
Biology: Pedigree Worksheet
Directions: Use the pedigrees below to answer the following questions.
1. What does a pedigree show?
2. Which members of the family are afflicted with Huntington’s disease? _____________________
3. There are no carriers of Huntington’s Disease: either you have it or you don’t. With this in mind, is
Huntington’s disease caused by a dominant or recessive allele? Explain.
4. How many children did individuals I-1 and I-2 have? __________________________________
5. How many girls did II-1 and II-2 have? __________ How many have Huntington’s disease? __________
6. How is individual III-2 and II-4 related? ____________________ I-2 and III-5? _____________________
7. If individual III-3 were to marry a man with Huntington’s disease (homozygous dominant), what would
be the chances of their children having the disease? Show the punnett square!
8. Based on your results in #7, do you feel III-3 should have children with her husband? Explain your
opinion.
Match the phrase with the letters (a, b, c, or d) on the pedigree. Some parts may be used more than once.
9. A person that has the trait _______
12. Represents a marriage _______
10. A male _______
13. A female _______
11. A carrier of the trait _______
14. Connects parents to their children _______
15. Is this disease caused by a recessive or dominant trait? Explain.
16. How many children did F and G have? ___________________
17. How many of these children have the disease? _______________________
18. A and E are the grandparents, how many grandchildren do they have? ______________________
19. How many people in the pedigree are both carriers AND women? ______________________
20. How are I and G related? ___________________________________
21. How are H and N related? ____________________________________
22. How many nieces and nephews does K have? _________________________
23. If C was to marry a carrier of this disease, what would the chance be that their children would have the
disease? Show the punnett square!