Two individuals with the following genotypes are crossed: GGHhmm X GghhMm Assuming that the three gene loci are unlinked, what is the expected proportion of offspring from this cross that are genotype GgHhmm?

1/8

Explanation:

The following cross is done:

GGHhmm X GghhMm

If genes are unlinked they assort independently, and we can analyze one at a time to obtain the proportions in the offspring, and then multiply those probabilities to get the proportion of appearance of the GgHhmm genotype.

Gene G/g

P: GG x Gg

F1: 1/2 GG, 1/2 Gg

Gene H/h

P: Hh x hh

F1: 1/2 Hh, 1/2 hh

Gene M/m

P: mm x Mm

F1: 1/2 Mm, 1/2 mm

Total proportion of GgHhmm genotype = 1/2 x 1/2 x 1/2 = 1/8