In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, W- means the individual has either the genotype WW or Ww. In summer squash, genotypes W- G- and W- gg are white, ww G- are yellow, and ww gg are green. W and G show independent assortment. What is the ratio of white : yellow : green among progeny of the cross Ww Gg × Ww Gg?
A)12:3:1
B)9:3:1
C)10:3:3
D)9:6:1
E)None of the answer options is correct.

Question

Quizplus · Accepted Answer

The cross Ww Gg × Ww Gg can be analyzed by considering each gene separately and then combining the results. For the W gene, the cross Ww × Ww produces 3/4 W- (WW or Ww) and 1/4 ww. For the G gene, the cross Gg × Gg also produces 3/4 G- (GG or Gg) and 1/4 gg. Combining these, the ratio of white (W- G- and W- gg) to yellow (ww G-) to green (ww gg) is 9/16 white (3/4 W- × 3/4 G- plus 3/4 W- × 1/4 gg), 3/16 yellow (1/4 ww × 3/4 G-), and 1/16 green (1/4 ww × 1/4 gg), which simplifies to 12:3:1.

In Genetics, the Dash Symbol (-) Is a "Wild Card