Genetics Worksheet

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Genetic Worksheet
Misanna Gordon
SCI 230
December 02, 2012
Mitzie Sowell

Associate Program Material

Genetics Worksheet

Review the images below and answer the follow-up questions.

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.

Cystic Fibrosis is considered to be a recessive trait. If a person has only one of the Cystic Fibrosis gene and one of the non-Cystic Fibrosis genes, the person could be a carrier of the Cystic fibrosis gene without having the Cystic Fibrosis disease. Referring back to the mentioning of Mendel, which states that the traits may not show up in a person but still can be passed down to the other generation. Mendel also mentioned that the inheritance of each of the trait can be determined by the genes that can pass down unchanged. Therefore if the Cystic Fibrosis gene is not present, it can become present dependent on the ratio of the amount of genes when it passes down.

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] A a]

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 with Huntington’s disease
unaffected female
Generation
I
II
III
IV
V
Pedigree showing inheritance of Huntington’s disease

B
B

Questions:

1. According to the pedigree, is Huntington’s disease 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, it is my belief that the Huntington’s disease is a recessive trait. My reason for the belief is that one of the family members at the beginning of the pedigree was affected by the disease. Also in the third generation, there was no family members affected as well. If the trait was dominant, more family members in the earlier stages of the pedigree would have been affected.

2. What would a Punnett square that shows how the first daughter in generation II (marked with a B) did not inherit Huntington’s disease look like?

[B]b]

[B]bb]

3. What is the role of chromosomes in the inheritance of genetic traits, such a cystic fibrosis and Huntington’s disease?

The genetic traits are carried by the chromosomes. Within the normal cell, the chromosomes each have two parts which is the...
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