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 cross would yield white and yellow progeny in the ratio of 1:1?
A)WW gg × ww gg
B)WW Gg × Ww GG
C)Ww Gg × Ww Gg
D)WW gg × ww GG
E)Ww Gg × ww GG

Question

Quizplus · Accepted Answer

To obtain a 1:1 ratio of white and yellow progeny, we need to cross a white (W- G- or W- gg) with a yellow (ww G-). The only option that will give us this type of cross is E) Ww Gg × ww GG. The heterozygous Ww and Gg parent will have a 50% chance of passing on the dominant W and G alleles, resulting in white progeny, and a 50% chance of passing on the recessive w and G alleles, resulting in yellow progeny.

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