Three QTLs representing genes PQR on different chromosomes i

Three QTLs representing genes P,Q,R on different chromosomes influence the amount of meat yielded by cattle. P,Q,R represent the additive alleles and p,q,r represent the non-additive alleles. You cross individual with the genotype Pp Qq Rr with individuals of genotype pp qq rr. How many different phenotypic classes would you obtain?

(Please show working)

Solution

The cross and it\'s result is shown below

From the table it can be seen that 6 different genotypes be formed. Since all the 3 additive alleles should be expressed for maximum activity, this cross may give rise to 6 different phenotypes