Introduction to Pedigrees

What is this pictured below?

Practice Pedigree 1:

​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. The pedigrees below trace the inheritance of the allele that causes albinism.

​1.  Number the generations and individuals.

2. In this family, how many individuals “show” the trait? & who are they?

3. How many men show the trait?

4. How many children does the couple from the first generation have?

Multiple Choice

How many kids did the mother and father from the first generation have?

• 2

• 4

• 5

• 6

Hotspot

In this pedigree chart, Huntington's Disease is the genetic disorder that is being traced throughout this family's bloodline. Click on the females that are expressing this trait in this family tree.

Hotspot

Who are the parents of person lll-4? Click on the two individuals within this pedigree chart.

Multiple Choice

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

• Grandpa and grandson

• Mom and son

• Uncle and nephew

• Grandma and grandson

Pedigree Practice 2:

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. The pedigrees below trace the inheritance of the allele that causes albinism.

1. Given the following genotypes, describe the phenotypes

(normal or albino)

AA = ____________________

Aa = ____________________

aa = _____________________

2. Label the generations and
individuals.

3. Figure out all the genotypes of each
individual given that all shaded shapes
express the trait.

​Pedigree Analysis

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

b) How many grandchildren? _____

c) How many of their grandchildren are albino?  ______

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

Multiple Choice

Huntington's Disease is recessive genetic disorder represented within all shaded shapes. What is the only possible genotype for person l-2?

• HH

• Hh

• hh

Multiple Choice

What is the genotype of the father?

• AA
• aa
• Aa
• AA or aa

Match

Match the following shapes to what they would represent on a pedigree chart.

male that DOES express the trait.

female that DOES express the trait.

female that does NOT express the trait.

male that does NOT express the trait.

• male that DOES express the trait.

• female that DOES express the trait.

• female that does NOT express the trait.

• male that does NOT express the trait.

Multiple Choice

The trait this pedigree traces is recessive because it skips a generation and individuals can be carriers. What is the most likely genotype for person III-3?

• GG

• Gg

• gg