Uop Sci/185

Associate Program Material

Genetics Worksheet

Review the images below and answer the follow-up questions. Each question is worth 20 points.
Key:
Male affected with cystic fibrosis Unaffected male Female affected with cystic fibrosis Unaffected female
Generation
I
II
III
IV
V
Pedigree showing inheritance of cystic fibrosis
A
Key: Male affected with cystic fibrosis Unaffected male Female affected with cystic fibrosis Unaffected female
Generation
I
II
III
IV
V
Pedigree showing inheritance of cystic fibrosis
A

Questions:

1. According to the pedigree, is cystic fibrosis inherited as a dominant or as a recessive traitKey: Male with Huntington’s disease unaffected male Female with Huntington’s disease unaffected female
Generation
I
II
III
IV
V
Pedigree showing Inheritance of Huntington’s disease
Key:
Male with Huntington’s disease unaffected male Female with Huntington’s disease unaffected female
Generation
I
II
III
IV
V
Pedigree showing Inheritance of Huntington’s disease
? Explain how you made your conclusion using evidence from the pedigree and the principles of genetics. According to the pedigree above this would be a recessive trait. The reason this is a recessive trait is because no family member at the beginning of the pedigree was affected. Also no family members in the third generation of the pedigree were affected as well. If this were a dominant trait I see it affecting more family members in the earlier stages of the pedigree.

2. What would a Punnett square that shows how the son in generation IV (marked with an A) inherited cystic fibrosis look like? | A | a | A | AA | Aa | a | Aa | aa |

Key: Male with Huntington’s disease unaffected male Female with Huntington’s disease unaffected female
Generation
I
II
III
IV
V
Pedigree showing inheritance of Huntington’s disease
Key:
Male with Huntington’s disease unaffected male Female