1. Review from Objective 1
Which of the following depicts a dominant genotype? (tall – dominant, short – recessive) Tt
Tall tt
Short
The answer is _______ because:

2. Answer
Which of the following depicts a dominant genotype? (tall – dominant, short – recessive) Tt
Tall tt
Short
The answer is _______ because:

3. A woman is homozygous dominant for wavy hair, what would her genotype be?
 HETEROZYGOUS
 HOMOZYGOUS RECESSIVE WW Ww ww

4. A woman is homozygous dominant for wavy hair, what would her genotype be?
 HETEROZYGOUS
 HOMOZYGOUS RECESSIVE WW Ww ww

5. If T is dominant for tallness, and t is recessive for short
If T is dominant for tallness, and t is recessive for short. What phenotype would a woman have if she was homozygous recessive?
Tall tt
Short

6. If T is dominant for tallness, and t is recessive for short
If T is dominant for tallness, and t is recessive for short. What phenotype would a woman have if she was homozygous recessive?
Tall tt
Short

7. TT and tt Tt and TT Tt and tt Tall and short
A man is heterozygous Tall and married a woman who was homozygous recessive short. What would be their genotypes?
TT and tt
Tt and TT
Tt and tt
Tall and short

8. TT and tt Tt and TT Tt and tt Tall and short
A man is heterozygous Tall and married a woman who was homozygous recessive short. What would be their genotypes?
TT and tt
Tt and TT
Tt and tt
Tall and short

9. How to predict offspring using the monohybrid squares
PUNNETT SQUARES!
How to predict offspring using the monohybrid squares

10. WHAT’S A PUNNETT SQUARE?
A diagram used to show the probability of certain traits being passed on from one generation to the next.
Developed by Reginald Punnett
WHAT IS PROBABILITY?
The likelihood of an event taking place (chance)
Can be expressed by a fraction (1/4) or a percent (25%) or a ratio (3:1)
Like flipping a coin!

11. MONOHYBRID PUNNETT SQUARE
Looking at ONE trait at a time.
Gamete genotypes are on the top and left sides
Offspring possibilities are inside the squares

12. STEPS FOR A MONOHYBRID: ONE TRAIT AT A TIME
1. Figure out the genotypes Rr x Rr
for each parent.
2. First parent genotype
is written on top (male)
3. Second parent is written
on the left side (female)
4. Fill in the inner boxes
with the alleles that they
fall under. R r R r R r RR Rr rr

13. Genotypes & Phenotypes
5. Monohybrid Results
Genotypes & Phenotypes
Genotype Fraction-
¼ BB, ½ Bb, ¼ bb
Phenotype Fraction-
¾ Big eyes, ¼ Small eyes
Genotype Percent-
25% BB, 50% Bb, 25% bb
Phenotype Percent-
75% Big Eyes, 25% Small eyes
Genotype Ratio- 1:2:1 (BB:Bb:bb)
Phenotype Ratio- 3:1 (Big:Small)

14. Practice 1: Male: Gg Female: Gg
G= Green
g= yellow
G g
GG Gg
Gg gg
G g
¼ GG, ½ Gg, ¼ gg
¾ green,
¼ yellow
Genotype Fraction: ____________ Phenotype Fraction: ____________
Genotype %: _________________ Phenotype %:_________________
Genotype Ratio: ______________ Phenotype Ratio: ______________
25% GG, 50% Gg, 25% gg
75% green,
25% yellow
1:2:1 (GG:Gg:gg)
3:1 (green:yellow)

15. Practice 2: Male: Gg Female: gg
G= Green
g= yellow
G g
Gg gg
g g
½ Gg, ½ gg
½ green,
½ yellow
Genotype Fraction: ____________ Phenotype Fraction: ____________
Genotype %: _________________ Phenotype %:_________________
Genotype Ratio: ______________ Phenotype Ratio: ______________
50% Gg, 50% gg,
50% green,
50% yellow
1:1 (Gg:gg)
1:1 (green:yellow)

16. The answer is ________ because:
Check yourself Which statement best explains the fact that some identical twins appear different from one another?
Their DNA is essentially the same and the environment plays little or no role in the expression of their genes
Their DNA is very different and the environment plays a significant role in the expression of their genes
Their DNA is very different and the environment plays little or no role in the expression of their genes.
Their DNA is essentially the same and the environment plays a significant role in the expression of their genes.
The answer is ________ because:

17. The answer is ________ because:
Check yourself Which statement best explains the fact that some identical twins appear different from one another?
Their DNA is essentially the same and the environment plays little or no role in the expression of their genes
Their DNA is very different and the environment plays a significant role in the expression of their genes
Their DNA is very different and the environment plays little or no role in the expression of their genes.
Their DNA is essentially the same and the environment plays a significant role in the expression of their genes.
The answer is ________ because: