1. Dihybrid Punnett Square
What is it?
A graphical grid showing the potential
offspring allele combinations for two
genes each having two alleles.

2. Cross parents that are heterozygous for pod color (Gg) and seed color (Yy). Both parents are GgYy!!! YIKES!!!!! Hint: FOIL
OFFSPRING
PARENT GY Gy gY gy P A R E N T GY
GGYY
GGYy
GgYY
GgYy Gy
GGYy
GGyy
GgYy
Ggyy
KEY:
GG = Green pod
Gg = Green pod
gg = yellow pod
YY = yellow seed
Yy = yellow seed
yy = green seed gY
GgYY
GgYy
ggYY
ggYy gy
GgYy
Ggyy
ggYy
ggyy

3. Interpreting a Punnett Square What does it tell us?
GGYY = green pod; yellow seed
ggyy = yellow pod; green seed Can you do the rest???
PARENT GY Gy gY gy P A R E N T GY
OFFSPRING
GGYY
GGYy
GgYY
GgYy Gy
GGYy
GGyy
GgYy
Ggyy
KEY:
GG = Green pod
Gg = Green pod
gg = yellow pod
YY = yellow seed
Yy = yellow seed
yy = green seed gY
GgYY
GgYy
ggYY
ggYy gy
GgYy
Ggyy
ggYy
ggyy

4. GY Gy gY gy GY Gy gY gy What are the ratios of phenotypes?
9 Green pod; yellow seed 3 Green pod; green seed
3 Yellow pod; yellow seed 1 Yellow pod; green seed
9:3:3:1
PARENT GY Gy gY gy P A R E N T GY
OFFSPRING
GGYY
GGYy
GgYY
GgYy Gy
GGYy
GGyy
GgYy
Ggyy
KEY:
GG = Green pod
Gg = Green pod
gg = yellow pod
YY = yellow seed
Yy = yellow seed
yy = green seed gY
GgYY
GgYy
ggYY
ggYy gy
GgYy
Ggyy
ggYy
ggyy