1. So I am looking at 2 characters how many traits am I studying? I WANT PURPLE FLOWERED, YELLOW- SEEDED PEA PLANTS

2. I have a purple flower I can start with…. But I don’t know if it’s homozygous or heterozygous SS or Ss?

3. Test cross! Used to figure out the genotype of an individual whose phenotype is dominant (purple in this case) What should we cross the purple flower with? What will give us clues about the genotype? A- another purple flower B- a white flower

4. So a test cross is a cross between an organism with a dominant phenotype and a homozygous recessive individual

5. Now on to the seed color… Yellow trait is dominant, what should the letters be to show seed color alleles? I have a yellow seeded plant. How do I determine if I should use it?

6. Now I know the genotypes of my purple and yellow seeded plants But what if I messed up and ended up with heterozygous individuals? How many purple flowered, yellow seeded offspring will I probably have? ….dihybrid cross! Remember the law of independent assortment

7. Dihybrid Cross A cross that involves two pairs of contrasting traits Draw the Punnett square with a cross of two hybrids for both flower color and seed shape What is the phenotypic ratio? (purple flower yellow seed: purple flower green seed: white flower yellow seed: white flower green seed)