Working with Pedigree Charts

Name

Ms. Kellock

Science - Period

Date

Working with Pedigree Charts

Green Gene

On the planet Dyejob, green hair is a recessive trait. The dominant gene produces black hair. Great Grandma and Great Grandpa Berg both have green hair, and so do their three children. They were surprised to find that three of their great grandchildren have green hair, too, even though all of their grandchildren have black hair. The Berg’s made a pedigree chart to show the inheritance of hair color in their family. Answer the following questions by interpreting the pedigree chart.

1.  Identify the symbols used in the pedigree chart by completing the key, including gender and traits. Your textbook has information about these symbols.

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2.  List the names of Grandma and Grandpa Berg’s children

3.  Name the children of Becky and Billy

4.  Identify the family members that are carriers for the green hair gene by coloring ½ their symbol.

5.  Using the letter B to represent the gene for hair color, what would be the symbol for green hair? For black hair?

6.  What is the genotype for great grandma Berg? for great grandpa Berg?

7.  Bobby and Beth are both heterozygous for green hair. What are their genotypes? X

8.  Bilbo does not have green hair. Is Bilbo a carrier?

Explain your answer

9.  How many generations are represented on this Berg Family pedigree?

10.  Bunny, who has blond hair, claims to be the long lost child of Great Grandma and Great Grandpa Berg. Should they include her as a daughter in their will?

Explain your answer

Huntington Disease (HD) causes progressive loss of cells in areas of the brain responsible for some aspects of movement control and mental abilities. A person with HD gradually develops abnormal movements and changes in cognition (thinking), behavior, and personality.

1.  There are no carriers for Huntingdon’s Disease – you either have it or you don’t. Using this information, is Huntingdon’s Disease caused by a dominant or recessive trait?

2.  How many children did individuals I-1 and I – 2 have?

3.  How many girls did II-1 and II-2 have? How many have HD?

4.  List the members of the family above afflicted with Huntingdon’s Disease

5.  How are individuals III-2 and II-2 related? I-2 and III-5?

6.  The pedigree to the right shows the passing of Hitchhiker’s thumb in a family. Is this trait Dominant or recessive?

7.  Explain how you know

8.  How are individuals II-5 and III-5 related?

9.  Identify 2 individuals with hitchhiker’s thumb.

10.  Identify 2 individuals that are carriers.

11.  Is it possible for individual IV-3 to be a carrier?

12.  The pedigree to the left shows the passing of colorblindness. Which sex can be carriers of this disorder?

13.  What type of inheritance does colorblindness follow?

14.  Explain why individual IV-7 has colorblindness.

15.  Why do all the daughters in generation II carry the colorblind gene?

16.  Identify a colorblind female.

Chapter 6.2 - Pedigrees 8/08