“Stronger” trait
Will show as long
as gene is present
Represented by
capital letter (B)
“Weaker” trait
Needs to have 2
to
show up
Represented by
lowercase letter (b)
What
YOU look like
Example: roller,
non-roller, red hair,
non-red hair
What
the genes
look like (letters of
genes)
Example: Rr, RR, rr
2
of the same alleles
(genes)
Example:
RR, rr
1
of the same alleles
(genes)
Example:
Rr
Homozygous Dominant = TT
13
• Homozygous
Dominant = TT
• (Homozygous)
Recessive = tt
• Heterozygous= Tt
Likelihood
that an
event will happen
Used to predict in
genetics
ALBINO
ANIMALS!
•Animals
with no
pigment
•Lack
of color in eyes
allows to see through to
blood vessel = red eyes
•Some
“normal” animals
carry the albinism gene
(a)
•Must have 2 recessive
genes for albinism (aa)
Now it’s time for
PUNNET SQUARES!
Chart
used to show
possible gene
combinations
Glue in the small piece
of paper you were
given in the remaining
space!
Normal
Squirrel
Phenotype: Normal
Genotype: AA or Aa
x
Albino
Squirrel
Phenotype: Albino
Genotype: aa
a
a
A
A
Aa
Aa
Aa
Aa
Chances:
100% not
albino
0 % albino
a
a
A
a
Aa
aa
Chances:
50% not
albino
aa
50 %
albino
Aa
A
a
A
a
AA
Aa
Chances:
75% not
albino
aa
25%
albino
Aa
Heterozygous
Heterozygous
Tongue Roller
Tongue Roller
Phenotype: Roller
Genotype: Tt
Phenotype: Roller
Genotype: Tt
Homozygous
Homozygous
Tongue Roller
Tongue Roller
Phenotype: Roller
Genotype: TT
Phenotype: Roller
Genotype: TT