Question

A space capsule crashes to earth with an alien life form aboard. Two creatures emerge from the capsule, one with green skin and one with yellow skin. The yellow creature soon gives birth to offspring fathered by the green creature, producing 12 green and 8 yellow offspring. Green skin in these diploid creatures is dominant to yellow skin. You are curious to find out if the number of offspring significantly different from expected Mendelian ratios, so you perform a chi-square test. What is the chi-square value for this cross

Answer 1

0.8

Explanation:

Given that, the green skin (G) is dominant to yellow (Y). Cross between the green creature and yellow creature will have the offspring with the following genotypes.

Gg* yy = Gy, Gy, gy, gy (Means, 1:1 ratio of green and yellow offspring, but the observed values are in 3:2 (12:8) ratio).

Now, the Chi-square value can be calculated as follows. (O= Observed, E= Expected)

See attachment for the chi square