The researchers also crossed mutant green plants with wild-type green plants. No
ID: 3257273 • Letter: T
Question
The researchers also crossed mutant green plants with wild-type green plants. Not surprisingly, the first generation was 100% green. In the second generation (F2), however, a new phenotype was observed in some of the plants: a transitional variegation occurring only on the first few leaves. (We will call them “transitional.”) Of the 85 plants obtained in F2, 65 were wild-type green, 15 variegated, and 5 transitional. The researchers hypothesized that these phenotypes are the result of two genes following a dominant epistatic model.
Using the four-step process, fill in the blanks.
2=
__Answer 1__. Round your answer to 3 decimal places.
DF = __Answer 2__. Give your answer as a whole number.
P-value = __Answer 3__. Round your answer to 3 decimal places.
Arabidopsis thaliana is a green-leafed plant, but a variegated type has green-and-yellow leaves. To investigate the mechanism of plant variegation, researchers created, in the DNA of the variegated Arabidopsis, a recessive mutation that suppresses variegation. When the green mutants were crossed with the variegated types, the first-generation plants were all variegated, thus confirming the recessive aspect of the mutation. In the second generation (F2), the researchers obtained 84 green plants and 216 variegated plants.The researchers also crossed mutant green plants with wild-type green plants. Not surprisingly, the first generation was 100% green. In the second generation (F2), however, a new phenotype was observed in some of the plants: a transitional variegation occurring only on the first few leaves. (We will call them “transitional.”) Of the 85 plants obtained in F2, 65 were wild-type green, 15 variegated, and 5 transitional. The researchers hypothesized that these phenotypes are the result of two genes following a dominant epistatic model.
Using the four-step process, fill in the blanks.
2=
Explanation / Answer
Ans: Expected count=row sum*column sum/total sum
Total sum=385
degree of freedom=(r-1)*(c-1)=(2-1)*(3-1)=2
p-value for chi square score of 90.47 and df=2 is 0.
Observed(O) Green variegated transitional Total gen1 84 216 0 300 gen2 65 15 5 85 Total 149 231 5 385 Expected(E) Green variegated transitional Total gen1 116.10 180.00 3.90 300 gen2 32.90 51.00 1.10 85 Total 149 231 5 385 (O-E)^2/E 8.88 7.20 3.90 31.33 25.41 13.75 Chi square 90.47