1. Chi- Squre Goodness of Fit Test From Ch 3 Will also include information on di-hybrid crosses

2. Outline Di-Hybrid Cross Mendel’s 2 nd Law Chi-Square Analysis corn data (phenotypes)

3. DIHYBRID CROSS Reveals Mendel’s 2 nd Law Principle of Independent Assortment 9:3:3:1

4. Independent assortment Refers to alleles on different chromosomes!

5. What is the P that there are yellow and round seeds? ¾ x ¾ = 9/16

6. Chi Square Statistical “Goodness of Fit Test” Why do we use it?. To find out determine if probability are due to chance alone. An example of how to calculate a Chi Square

7. Application of Chi Square

9. Corn genetics Lab

10. Objective Complete corn worksheet Set up Punnett Squares using the genotypes given Compare expected data to observed data Perform Chi Square Analysis

11. Variation of colors—Why?

12. Corn Kernel Color Color of aleurone masks endosperm color Only with colorless aleurone can endosperm color be determined Determined by several genes Refer to genotypes in lab manual!

13. Gene interaction can occur: Epistasis is a form of gene interaction in which one gene masks the phenotypic expression of another.

14. Today there are: 3 crosses of corn Multiple alleles are tested for expression in F2 generation F1 X F1

15. Note color differneces Cross C Cross D (darker color is purple) Cross F (call purple, may look red!)

16. Cross C F 1 phenotype F 1 X F 1 genotypes Yellow YYC’Rr X YYC’Rr

17. Cross D F 1 phenotype F 1 X F 1 genotypes Purple yyPpRr X yyPpRr

18. Cross F F 1 phenotype F 1 X F 1 genotypes Purple yyCcRr X yyCcRr

19. Genetic information regarding the corn color patterns are provided in your lab manual. The basis of these color patterns. CORN WORKSHEET IS DUE 2/28/08