1. Presented by; Mrs. Barr Mrs. Batten
Punnett square
Presented by;
Mrs. Barr
Mrs. Batten

2. Tool used to predict or identify hereditary results
Punnett Square
Tool used to predict or identify hereditary results

3. Alleles
Each cell has 2 for each trait Can be the same– AA, aa called homozygous Can be different – Aa called heterozygous

4. Genotype Vs. Phenotype
Genotype– the actual genes ---- RR, Rr. rr Phenotype – the way it looks---- Red, Red, white

5. How to make a punnett Square
Decide which letters to use to represent the trait
Ie. Trait is flower color we will use the letter R
Trait is height we could use the letter T
Hair type we could use the letter W

6. How to make a punnett Square
2. Determine if the parent is heterozygous or homozygous for that trait
Homozygous could be RR, or rr
Heterozygous would be Rr

7. How to make a punnett Square
3. Know if they are dominant or recessive
Capital letters represent dominant
Lower case letters represent recessive

8. How to make a punnett Square
4. Draw the box

9. How to make a punnett Square
Fill in the letters for each parent
R r R r

10. How to make a punnett Square
6. Fill in the grid
R r R r RR Rr rr

11. Let’s Practice
Tall is dominant (T) Mom is heterozygous Dad is heterozygous
Lets draw the punnett square for them. TT Tt Tt tt

12. Ratios
Genotypes: TT 25% Tt 50% tt 25%
Phenotypes Tall 75% Short 25%