In tomato plants, a gene controlling fruit shape has 2 alleles: O (round) and o (oval). A gene controlling inflorescence (position of the flowers) has two alleles: S (simple) and s (compound). A pure-breeding plant with oval fruit and simple inflorescence is crossed to a pure-breeding plant with round fruit and compound inflorescence. All the offspring have round fruit and simple inflorescence. The offspring are then crossed to plants with oval fruit and compound inflorescence. The phenotypes of this second generation are
Oval simple 200
Round compound 190
Oval compound 50
Round simple 60.
Which statement about the genes is true?
A) The alleles of one gene assort independently of the alleles of the other gene.
B) The recombination frequency between the genes is more than 50 per cent.
C) The gene loci are on separate chromosomes.
D) The genes show incomplete dominance.
E) The genes are linked.

Question

Quizplus · Accepted Answer

The observed phenotypes and their ratios suggest linkage between the genes controlling fruit shape and inflorescence, as the parental phenotypes are more common than the recombinant types, indicating that the genes do not assort independently and are likely on the same chromosome with a recombination frequency less than 50%.

In Tomato Plants, a Gene Controlling Fruit Shape Has 2