Question

A mating of two red-colored insects produced 1080 offspring, including 240 that were black. You suspect that insect color is under the control of a single gene, with the dominant allele producing red color, and the recessive allele producing black. Therefore, you propose a null hypothesis of a simple monohybrid cross. What is the chi-square value for this experiment?

A. 0.37
B. 1.11
C. 2.22
D. 3.33

Answer 1

The chi-square value for this experiment is 2.22.

Step-by-step explanation:

The chi-square value for this experiment can be calculated using the formula:

χ² = Σ((Observed - Expected)² / Expected)

In this case, the observed values are obtained from the mating of two red-colored insects, which produced 1080 offspring, including 240 that were black. The expected values can be calculated based on the assumption of a monohybrid cross, where the dominant allele produces red color and the recessive allele produces black color. Assuming a 3:1 phenotypic ratio with 3/4 red and 1/4 black, we can calculate the expected values as: Expected red = (3/4) * 1080 = 810 and Expected black = (1/4) * 1080 = 270.

Substituting the values into the chi-square formula:

χ² = ((240 - 270)² / 270) + ((840 - 810)² / 810)

χ² = 600/270 + 900/810 = 2.22

Therefore, the correct answer is C. 2.22.