Chapter 10 Reminders
1. A genotype is an allele combination like GG, Gg, & gg.
2. A genotype determines the phenotype; G=green & g=yellow
GG or Gg=green b/c of the rule of dominance; but gg=yellow
b/c both recessive alleles must be present to display the
recessive trait.
3. Remember homozygous dominant=GG; heterozygous=Gg; &
homozygous recessive=gg
4. Remember each parent contributes only 1 allele to the offspring.
If one parent is homozygous dominant & the other parent is homozygous
recessive, then the possible outcomes would be:
G
G
g
Gg
Gg
g
Gg
Gg
5. If both parents are heterozygous, then the possible outcomes would be:
G
g
G
GG
Gg
g
Gg
gg
Here there are 3 different possible genotypes: GG, Gg, & gg.
However, there are only 2 possible phenotypes: green or yellow.
6. When 2 traits are studied, there are 2 sets of alleles: G=green; g=yellow;
R=rough; & r=smooth.
7. If one plant is homozygous dominant for both traits: GGRR and another plant is
homozygous recessive for both traits: ggrr then all of the offspring will be:
heterozygous:GgRr.
8. If 2 heterozygous plants cross pollinate(GgRr x GgRr), then the possible
outcomes would be:
GR
GR
Gr
gR
gr
GGRR
GGRr
GgRR
GgRr
Gr
GGRr
GGrr
GgRr
Ggrr
gR
GgRR
GgRr
ggRR
ggRr
GgRr
Ggrr
ggRr
ggrr
gr
9. There are many possible genotypes, but only 4 phenotypes: Green, rough;
green, smooth; yellow, rough; & yellow smooth.
The red squares (9 out of 16) represent the genotypes that result in the
phenotypes: green, rough.
The green squares (3 out of 16) represent the genotypes that result in the
phenotypes: green, smooth.
The yellow squares (3 out of 16) represent the genotypes that result in the
phenotypes: yellow, rough.
The blue square (1 out of 16) represents the genotype that results in the
phenotype: yellow, smooth.