Question

The second F₂ (cross 2) is from a yellow starchy corn crossed with a white sweet corn. The F₁ was all yellow starchy.  Propose an inheritance pattern for this trait to account for the segregation pattern you observe (how many genes and what type of gene action controls the trait), and test your hypothesis with a Chi-square statistic. For the Chi Square problems show observed, expected, calculations, table P value for appropriate degrees of freedom and your conclusion. Note that your ratio must agree with known and accepted genetic ratios.

Determine the mode of inheritance of the characteristic in question. In some cases you may need to test several hypotheses in order to determine which best accounts for the segregation in your material. The Chi-square test gives you probability values associated with a given hypothesis. From these results, you determine the hypothesis that best fits your data, i.e. less deviation between observed and expected results. If you have 2 or more hypotheses that have approximately the same "goodness-of-fit", you need to discuss how you might design further work to determine which one is most likely.

CROSS 2 WITH CORN: F2 after Dihybrid Cross and Selfing of F1

Yellow Starchy:Yellow Sweet:White Stachy:White Sweet

1.    101:35:34:14

2.    101:43:40:10

3.    108:33:38:8

4.    89:48:42:6

5. 61:27:26:6

6. 62:17:29:5

7.    106:47:44:16

8.    135:35:50:17

Answer 1

7th option is showing the ratio of dihybrid cross that is 9:3:3:1 here the observed value is little bit deviate from the expected value .

Observed value= 106:47:44:16

Expected value = 96:48:48:16

Chi square test= (O-E)²/E

(106-96)²/96 + (48-47)² /48+ (48-47)² /48+ (16-16)²/16= 0.188

Degree of freedom is 1 because (n-1)

Here n=2 (number of variables)

At 0.05 p value taking the significance level at 1degree of freedom = 0.004(from p value chart)

Here p value < 0.188 (significance value)

There is no significance different in observed and expected value .