University:
Arizona State University
Course:
BIO 181 | General Biology I
Academic year:

2022
Views:

117

Pages:

3
Author:

Hallie Randolph

Name__________________________________ Date: __________________ Biology I Pedigree Worksheet A family tree of sorts is called a pedigree. The symbols used for a pedigree are: female, unaffected Siblings are placed in birth order from left to right and are labeled with Arabic numerals. Each generation is labeled with a Roman numeral. Therefore, the male exhibiting the trait in the pedigree below in the bottom, center would be identified as III-4. female, affected male, unaffected male, affected 1 I 1 1 II 2 = HuntingtonÕs Disease 2 4 5 3 6 7 8 III 1 2 3 4 5 1. Which members of the family above are afflected by HuntingtonÕs Disease? I - 1. II - 2, 3 , 7. III - 3 2. There are no carriers for HuntingtonÕs Disease- you either have it or you donÕt. With this in mind, is HuntingtonÕs disease caused by a dominant or recessive trait? It is a dominant trait 3. How many children did individuals I-1 and I-2 have? 6 4. How many girls did II-1 and II-2 have? 2 5. How are individuals III-2 and II-4 related? ii - 4 is iii - 2's uncle 2 I II III IV 12. The pedigree above shows the passing on of colorblindness. What sex is MOST likely to be carriers of colorblindness? Females 13. Why does individual IV-7 (a female) have colorblindness? Its because the mom is a carrier, and the dad has the disease. 14. Why do all the daughters in generation II carry the colorblind gene? They must have the effected X chromosome that they get from their father. 15. List 2 IV generation colorblind males. IV - 1 and IV - 5 3 16. Is this trait dominant or recessive? Explain your answer. It's recessive because only 3 people have the disease. 17. What gave you the essential information to decide that II-3 and II-4 were heterozygous? Since the trait is recessive, a person must receive, a person must receive both affected chromosomes to recieve the trait, therefore causing a heterozygous. 18. Brown eyes are a dominant eye-color allele and blue eyes are recessive. A brown-eyed woman whose father had blue eyes and whose mother had brown eyes marries a brown-eyed man whose parents are also brown-eyed. They have a son who is blue-eyed. Draw a pedigree (info above) showing all four grandparents, the two parents, and the son. Indicate each individuals possible genotypes. BB bb bb I II Bb Bb BB III BB