Question

in the garden pea, yellow cotyledon color is dominant to green, and inflated pod shape is dominant to the constricted form. considering both of these traits jointly in self-fertilized dihybrids, the progeny appeared in the following numbers: 193 green, inflated 184 yellow constricted 556 yellow, inflated 61 green, constricted what is the chi-square value?

Answer 1

Total chi-square: 0.65825. The P-value is greater than 0.05, so we fail to reject the hypothesis that the genes for yellow cotyledon color and inflated pod shape assort independently. Therefore, there is no evidence to suggest that the two traits are linked.

How can you solve for the chi-square value?

Hypothesis: The genes for yellow cotyledon color and inflated pod shape assort independently.

Expected ratios:

Yellow, inflated: 9/16

Green, inflated: 3/16

Yellow, constricted: 3/16

Green, constricted: 1/16

Chi-square calculation:

Category Expected Observed Deviation Deviation²
`(Deviation^2)/(Expected)`

Yellow, inflated 556.5 556 -0.5 0.25 0.00045

Green, inflated 193.5 193 -0.5 0.25 0.00129

Yellow, constricted 193.5 184 -9.5 90.25 0.46643

Green, constricted 64.5 61 -3.5 12.25 0.19008

Total chi-square: 0.65825

Degrees of freedom: 3 (number of categories - 1)

P-value: 0.886 (from chi-square table with 3 degrees of freedom)

Conclusion:

Since the P-value is greater than 0.05, we fail to reject the hypothesis that the genes for yellow cotyledon color and inflated pod shape assort independently. Therefore, there is no evidence to suggest that the two traits are link