If we set up a mating between plants Aa Bb Cc X Aa Bb Cc wha

If we set up a mating between plants (A/a; B/b; C/c) X (A/a; B/b; C/c), what fraction of the offspring will show all dominant phenotypes? (assume A is dominant over a; B is dominant over b; C is dominant over c).

Solution

Since this is a trihybrid cross and the cross will give 8 gametes from both the set of parents which after mating will produce 64 different phenotypes. Out of the 64 phenotypes, 8 will be unique. The ratio for the trihybrid cross is 27:9:9:9:3:3:3:1 which means that the 27 phenotypes will show the dominant allele for all the three genes. So the fraction will be 27/64 which will give the fraction of dominant phenotypes among all the kind pf phenotypes.