Pedigree Intro

Pedigree Chart Notes

What are they & how are they used?
Pedigree are genetic charts that are used to
track a trait in a family. Pedigrees show the
pattern of inheritance that may help scientists determine if a trait is dominant or recessive.

Pedigree Charts

We will be using
shapes instead of
letters…well mostly

Multiple Choice

Traits can be dominant or recessive

• True

• False

Horizontal Lines

Horizontal lines connect partners

Parts of the Pedigree

Romantic partners

NOT project partners!

Roman Numerals

Roman numerals show the generation
that each row belongs to. For examples, row Ⅱ is the second generation.

Parts of the Pedigree

Must use roman

numerals NOT normal

numerals!

Multiple Choice

If you see the the roman numeral , III, by a row in a Pedigree Chart what generation is it?

• First

• Second

• Third

• Fourth

Vertical Lines

A vertical line that branches shows offspring.

Parts of the Pedigree

This is where normal
numbers come into

play.

Shapes

Circles represent females and squares males.

Parts of the Pedigree

Told you there would

be shapes!

Labelling

Label what the relationship is between 1&2 and 2&3

Drag labels to their correct position on the image

Siblings

Daughter

Married

Offspring

Parts of the Pedigree

Siblings

Partners

Shading

Shading shows the

inheritance of the trait

studied.

Parts of the Pedigree

The shading means
they have the trait.

What does the half shaded mean?

Glossary

Unaffected: the individual
does not have the trait or
the allele for it. Normal.

Parts of the Pedigree

Unaffected

Male

Unaffected

Female

Female
Carrier

Male
Carrier

Affected
Female

Affected

Male

Carrier: the individual has
one allele for the trait, but does not show it. Heterozygous

Affected: the individual has the trait being studied.

Multiple Choice

What is the difference between heterozygous and homozygous?

• Heterozygous means two different alleles. Homozygous means the same.

• Homozygous means two different alleles.. Heterozygous means the same.

• they are the SAME!

Dropdown

A circle or square the is half shaded is a ​

Select answer

​

Practice Problem

Complete using your notes

We will be going
over this together!

Multiple Choice

What is the relationship between II-1 & II-2?

• Siblings

• Marriage

• Offspring

Multiple Choice

How many children do I-3 & I-4 have?

• 2

• 1

• 3

Multiple Choice

Is sickle cell a dominant or recessive disorder?

(Remember if there if NO fully shaded person in each generation it is recessive)

• Recessive

• Dominant