1. Corn Genetics & Chi- Square Goodness of Fit Test
Pedigrees and probability analysis to follow.

2. Outline Highlight some key points in syllabus
Corn color and collection of data (phenotypes)
Chi-Square Analysis

3. Corn genetics Lab

4. Application of Chi-Square Analysis
The color pattern in corn is due to multiple genes
Are variations in number of observed phenotypes due to chance alone?

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

6. Variation of colors—Why?

7. 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!

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

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

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

11. Cross C
F1 phenotype
F1 X F1 genotypes
Yellow
YYC’Rr X YYC’Rr

12. Cross D
F1 phenotype
F1 X F1 genotypes
Purple
yyPpRr X yyPpRr

13. Cross F
F1 phenotype
F1 X F1 genotypes
Purple
yyCcRr X yyCcRr

14. 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

16. Application of Chi Square

17. Genetic information regarding the corn color patterns are provided in your lab manual.
CORN WORKSHEET IS DUE 3/5