1. + Intro to Punnett Squares Mrs. MacWilliams Biology

2. + REVIEW THE PARENTS CAN ONLY GIVE ONE OF EACH HOMOLOGOUS CHROMOSOME. BUT, THERE ARE 2 DIFFERENT CHROMOSOMES EACH CAN GIVE!

3. + Punnett Squares – 7 Steps We will use 7 STEPS to complete punnett squares. Make sure you complete ALL 7 STEPS for every assignment and test and quiz.

4. + Step 1 List the type of cross (P, F1, F2) Parental or Purebread P ALWAYS 2 homozygous individuals First Filial or F1 generation Term used to describe the offspring obtained from a P generation ALWAYS 2 heterozygous individuals Second Filial or F2 generations Term used to describe the offspring obtained from two individuals from the F1 generation Any other combination (hetero x homo)

5. + Step 2 List the gender of the parent Symbol represents male Symbol represents female

6. + Step 3 List the genotype of the parents Genotype – the pair of alleles in the cells of an organism. The actual GENES in the pair

7. + Step 4 List the phenotype of parents Phenotype the organisms appearance of the expressed trait. The Photo of what the organism looks like The Physical traits of what it looks like

8. + Step 5 Complete the Punnett Square A grid that uses symbols to show the possible gene combination from a cross.

9. + Step 6 List Genotypic Ratio of cross Homozygous Dominant: Heterozygous: Homozygous Recessive YY: Yy: yy

10. + Step 7 List Phenotypic Ratio of cross Dominant: Recessive Yellow: green

11. + Generation Ratios! KNOW THESE!!!!!  Parent (P) generation Monohybrid cross: genotype 4:0 phenotype 4:0 Dihybrid cross: genotype 16:0 phenotype 16:0  First Filial (F1) generation Monohybrid cross: genotype 1:2:1 phenotype 3:1 Dihybrid cross: genotype 1:2:2:4:1:2:1:2:1 phenotype 9:3:3:1 Trihybrid cross: phenotype 27:9:9:9:3:3:3:1 Symbol represents female

12. + Monohybrid Cross A cross that involve ONLY ONE trait Ex: Seed color We will now complete a P generation Punnett Square and an F1 generation Punnett Square

13. +