<meta http-equiv="refresh" content="1; url=/nojavascript/"> Pedigree Analysis | CK-12 Foundation
Skip Navigation
You are reading an older version of this FlexBook® textbook: CK-12 Life Science Concepts For Middle School Go to the latest version.

3.16: Pedigree Analysis

Difficulty Level: At Grade Created by: CK-12
Practice Pedigree Analysis
Practice Now

What's a pedigree?

When you are talking about a pedigree dog, it means the dog is purebred. Through selective breeding, the dog has all the traits of that particular breed. When talking about genetics, however, a pedigree is a chart that helps show family relationships.

Pedigree Analysis

A pedigree is a chart that shows the inheritance of a trait over several generations. A pedigree is commonly created for families, and it outlines the inheritance patterns of genetic disorders. Pictured below is a pedigree displaying recessive inheritance of a disorder through three generations ( Figure below ). From studying a pedigree, scientists can determine the following:

  • If the trait is sex-linked (on the X or Y chromosome) or autosomal (on a chromosome that does not determine sex).
  • If the trait is inherited in a dominant or recessive fashion.

Sometimes pedigrees can also help determine whether individuals with the trait are heterozygous or homozygous.

Symbols of a pedigree, and an example pedigree

In a pedigree, squares symbolize males, and circles represent females. A horizontal line joining a male and female indicates that the couple had offspring. Vertical lines indicate offspring which are listed left to right, in order of birth. Shading of the circle or square indicates an individual who has the trait being traced. In this pedigree, the inheritance of the recessive trait is being traced. A is the dominant allele, and a is the recessive allele.


  • A pedigree is a chart which shows the inheritance of a trait over several generations.
  • From studying a pedigree, scientists can determine if a trait is sex-linked or autosomal.

Explore More

Use the resource below to answer the questions that follow.

  1. What is Whirling Disorder?
  2. Is Whirling Dosorder inherited in a dominant or recessive mannor? Why?
  3. Individual 5 does not have Whirling disorder, but what colored pieces does it have that potentially could have carried the gene for Whirling Disorder? From whom did he inherit these pieces.
  4. Which puzzle piece (gene) is responsible for Whirling Disorder?


  1. What is a pedigree?
  2. How might a pedigree aid a scientist?




On any chromosome other than the sex chromosomes.


Chart which shows the inheritance of a trait over several generations.


On the X or Y chromosome.

Image Attributions


Difficulty Level:

At Grade


7 , 8

Date Created:

Nov 29, 2012

Last Modified:

Jan 12, 2015
Files can only be attached to the latest version of Modality


Please wait...
Please wait...
Image Detail
Sizes: Medium | Original

Original text