Pedigree Webquest

Part One:

1. Go to the following link:

2. Click on the introduction.

1. Why do scientists use pedigree charts?

3. Now click on “task” and read how to help Barbie and Ken.

  1. What symbols may be used on the pedigree?
  1. How do you know the differences between generations?

4. Now click on “process”. You will have to travel to a different website to answer the questions below (it should link from the webpage) or go to

1. What kinds of information are found on a pedigree chart?

2. Draw the symbol that represents a male.

  1. Draw the symbol that represents a female.
  1. What does a line in between two individuals represent?
  1. What is meant by an affected individual? How is an affected person represented on a pedigree chart?
  1. What is a generation? How many generations are depicted in the pedigree at the bottom of the page?
  1. Look at the top pedigree. How many children does that couple have? What are the sexes of the children?
  1. Look at the bottom pedigree. How many children does the original couple have? Are any of these children affected individuals? Explain.
  1. In the bottom pedigree, in the fourth generation, list the sex of each child from oldest to youngest.

5. Click on the next website: and answer the following questions:

  1. What are monozygous twins? How are they represented on a pedigree chart?
  1. What are dizygous twins? How are they represented on a pedigree chart?

Part Two:

1. Draw a pedigree chart for the following family. Tom and Elizabeth are grandparents. They have 3 children, Sarah, Jennifer, and Linda. Sarah is married to Jacob and they have a daughter named Leah. Jennifer is married to Chris and they have 3 children: Alice, Joseph, and John. Linda is divorced and has 2 daughters, Mary and Anna. Please refer back to the two links if you are not sure about how to depict this information. Be sure that you use the appropriate symbols, designate the different generations properly, and include the correct name and gender.

2. Answer the following questions using the next website regarding sex-linked disorders: and go to “How is it inherited?”

  1. How does a boy get hemophilia?
  1. How does a girl become a carrier?
  1. If a woman is a carrier and the male does not have hemophilia, draw a Punnett Square and indicate the possible outcome (phenotype and percentages).

Part Three: Now use the information that you learned about Hemophilia to complete your pedigree chart from Part two of this lesson. Indicate that Tom, Linda, John and Chris have hemophilia by shading in the symbols that represent them in the Pedigree Chart.

  1. Explain how hemophilia is inherited.
  1. Describe which parent gave John the defective allele for hemophilia and explain how you know.
  1. Indicate how hemophilia is passed through the family and eventually to John. Include the genotypes and phenotypes of his parents, Jennifer and Chris, as well as his grandparents, Tom and Elizabeth.

Part Four: Testcrosses are crosses that are done to predict what possible outcomes two parents may have. In the following exercise you will do a test cross to show how a breeder could manipulate traits. Go to the following website:

Scroll down to the testcross section. Complete all the testcross activities. Stop at incomplete dominance. When you have finished, please call your teacher over and have her look over it and then sign below.

Teacher’s Signature: ______