Pedigrees Practice - Human Genetic Disorders

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In humans, albinism is a recessive trait. The disorder causes a lack of pigment in the skin and hair, making an albino appear very pale with white hair and pale blue eyes. This disorder can also occur in animals, a common albino found in a laboratory is the white rat.

1. Given the following genotypes, describe the phenotypes (normal or albino)

AA = ________________________________
Aa = ________________________________
aa = ________________________________

Fill out the blanks on the pedigree 

pedigree chart

a) How many children does the couple have? _______
b) What is the sex of the oldest child? _____
c) How many grandchildren does the couple have? _____

2. Fill out the blanks of the pedigree (AA, Aa, or aa)

a) How many children did the original couple have? ___

b) How many grandchildren do they have? ______

c) How many of their grandchildren are albino? _____

d) Create an extension to the pedigree to show the youngest granddaughter marrying and having a son who is NOT albino.

pedigree chart

3.  The following pedigree shows the inheritance of Tay-Sachs in a family. Tay-Sachs is a recessive disorder that causes cells to be unable to break down waste products. These wastes build up in brain cells and cause damage and eventual death.  Fill out the genotypes for each of the family members.

pedigree  chart

4.  This pedigree shows the inheritance of cystic fibrosis in a family. This disease causes mucus to build up in the lungs, leading to breathing difficulty and infections

FF = ________________________________
Ff= ________________________________
ff = ________________________________

Fill out the genotypes of each of the family members.

Add to the chart to show the youngest male (3rd generation) marrying and having a child with CF.

5.  The pedgree shows the inheritance of sickle cell disease (recessive). Fill out the genotypes of the family.

pedigree chart

Other Resources

Analyzing Human Pedigrees (Basic)

Analyzing Pedigrees of Sickle Cell Inheritance

The Inheritance of Sickle Cell Anemia - Pedigree Practice

Analyzing Pedigrees (AP Bio)

Exploring Autosomal Dominant Traits