Names ___________
_________________
_________________
_________________
How Are Traits Inherited?
The characteristics that help to identify living things are called traits. All living
things have particular traits that help to identify them. Traits are controlled by genes.
Offspring inherit genes for various traits from their parents.
Different traits may be either dominant or recessive. When there are two genes
for a dominant trait (1,1) the offspring has that trait. When there are two genes for a
recessive trait (2,2) the offspring has the recessive trait. But if there is one gene for the
dominant trait and one gene for the recessive trait (1,2) then the dominant trait will
appear. A recessive trait can show up only if both genes are for the recessive trait.
You will be using gene cards to help you figure out how dominant and recessive
genes work. You have 8 gene cards, 4 Tall (1) gene cards and 4 short (2) gene cards.
These cards represent tallness and shortness genes in pea plants. You will only use four
cards at a time, 2 for mom and 2 for dad.
1. Place two Tall (1) gene cards together. Will the pea plant be tall or short? ______
2. Place two short (2) gene cards together. Will the pea plant be tall or short? _____
3. Place one Tall (1) gene card with one short (2) gene card. Will the pea plant be
tall or short? ____________________
Try these crosses:
1. Tall (1,1) with Tall (1,1)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (1,1) Tall pea plant is crossed with
another (1,1) Tall pea plant. Take one gene from mom and one gene from dad. Will
the pea plant be tall or short? _____________________
b. Are any other combinations possible? _____________
Draw a
Punnett
Square for
this cross.
2. Tall (1,1) and Tall (1,2)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (1,1) Tall pea plant is crossed with
another (1,2) Tall pea plant.
a. Take a Tall (1) gene from mom and the Tall (1) gene from dad.
Will the pea plant be tall or short? _____________________
b. Take a Tall (1) gene from mom and the short (2) gene from dad. Will the pea
plant be tall or short? _____________________
c. Are any other combinations possible? _______
Fill in the
Punnett
Square for
this cross.
3. Tall (1,2) and Tall (1,2)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (1,2) Tall pea plant is crossed with
another (1,2) Tall pea plant.
a. Take a Tall (1) gene from mom and the Tall (1) gene from dad.
Will the pea plant be tall or short? _____________________
b. Take a Tall (1) gene from mom and a short (2) gene from dad. Will the pea
plant be tall or short? _____________________
c. Take a short (2) gene from mom and a short (2) gene from dad. Will the pea
plant be tall or short? _____________________
d. Are any other combinations possible? __________
Fill in the
Punnett
Square for
this cross.
4. Tall (1,1) and Short (2,2)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (1,1) Tall pea plant is crossed with a
(2,2) short pea plant.
a. Take a Tall (1) gene from mom and a short (2) gene from dad.
Will the pea plant be tall or short? _________________
b. Are any other combinations possible? _________
Fill in the
Punnett
Square for
this cross.
5. Tall (1,2) and Short (2,2)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (1,2) Tall pea plant is crossed with a
(2,2) short pea plant.
a. Take a tall (1) gene from mom and a short (2) gene from dad. Will the pea plant be
tall or short? _____________
b. Take a short (2) gene from mom and a short (2) gene from dad. Will the pea plant
be tall or short? __________________
c. Are any other combinations possible? ____________
Fill in the
Punnett
Square for
this cross.
6. Short (2,2) and Short (2,2)
(Mom)
(Dad)
Use your gene cards to see what will happen if a (2,2) short pea plant is crossed with
a (2,2) short pea plant.
a. Take a short (2) gene from mom and a short (2) gene from dad. Will the pea plant
be tall or short? ____________________
b. Are any other combinations possible? ____________
Fill in the
Punnett
Square for
this cross.
Tall
(1)
Tall
(1)
Short
(2)
Short
(2)
Tall
(1)
Tall
(1)
Short
(2)
Short
(2)
Tall
(1)
Tall
(1)
Short
(2)
Short
(2)
Tall
(1)
Tall
(1)
Short
(2)
Short
(2)