Pedigrees

Punnett Squares and Pedigrees

​Punnett squares

Multiple Choice

Heterozygous or homozygous?

BB

• heterozygous

• homozygous

Multiple Choice

Heterozygous or homozygous?

Bb

• heterozygous

• homozygous

Multiple Choice

Heterozygous or homozygous?

bb

• heterozygous

• homozygous

Multiple Choice

Genotype or phenotype?

• genotype

• phenotype

Multiple Choice

Genotype or phenotype?

Bb

• genotype

• phenotype

Remember for a dominant trait to be expressed, the alleles can be heterozygous or homozygous.

You only need one dominant allele for a dominant trait to show up.

Multiple Select

Scientists in Bikini bottom are investigating the genetic makeup of the organisms in their community. Select all of the genotypes below that are heterozygous.

• TT

• Bb

• DD

• Ff

• tt

Multiple Select

Which of these genotypes are homozygous?

• Ff

• tt

• dd

• bb

• BB

Multiple Choice

How chance the offspring born from this cross will have a homozygous dominant genotype?

• 25%

• 50%

• 75%

• 100%

Multiple Choice

If 3 out of 4 pea plants were purple, what percentage of the flowers were purple?

• 25%

• 50%

• 75%

• 100%

Multiple Choice

What are the chances that the offspring will have homozygous recessive traits?

• 1 in 4

• 3 out of 4

• 75%

• 50%

Multiple Choice

The dominant trait is

• yellow pea seeds
• green pea seeds
• there is no dominant seed
• Jolly green giant

Pedigree Charts

• Show relationships within a family
• In genetics: Used to show how an

inherited trait is passed through a family

Example of Trait = Albinism

Symbols

• Circle = female
• Square = male
• Normal or without trait=unshaded

• Trait = shaded

Dropdown

The female individual with the trait is ​

Select answer

​

Select answer

symbol. The male without the trait is​ ​

Select answer

​

Select answer

symbol.

Symbols

• If an individual

has one
recessive allele
for a trait, the
person is a
carrier. This is
shown with a
half-shaded
square or circle.

Dropdown

The difference between a carrier and one who expresses the trait is ​

Select answer

symbol. This usually means the trait is ​

Select answer

.

Symbols

• Married couple or

couple producing offspring
=horizontal line connecting
midpoint of circle and square

Symbols

• One offspring

• Multiple Offspring

How do you differentiate between a brother and sister
and a husband and wife on a pedigree?
for siblings the horizontal line is connected above the symbol.

Generations

• Each generation

is (often) labeled
with a Roman
numeral.

• Oldest generation

at top of pedigree

• Current

generation at
bottom

Labelling

Label the correct parts

Drag labels to their correct position on the image

Expressed Trait

Current Generation

Oldest Generation

Multiple Choice

How do they typically label each generation?

• Roman Numerals

• Alphabetically

• Naming Parental Generation

Generations

• Individuals in

each generation
may be
numbered or
named.

• Siblings are

placed in birth
order from left to
right.

1 2

1 2 3 4 5 6

1 2 3 4 5

Multiple Choice

Who was the first person to display the trait?

• Grandfather

• Grandmother

• Parent

• Aunt

Drag and Drop

This trait appears to be a ​

Placeholder

trait.

Drag these tiles and drop them in the correct blank above

recessive

dominate

deadly

Polydactyl Trait

• Based on the

pedigree chart, is
the trait for
multiple digits
(fingers and toes)
dominant or
recessive?

• How can you tell?

Analyzing a Trait

• Sometimes a

pedigree is
drawn without
the carriers
shown.

Open Ended

Is this trait dominate or recessive? How can you tell?