Solutions For An Introduction to Genetic Analysis Chapter 4 Problem 24P

The chromosome 3 in corn has three loci – b, for plant color booster, v, for virescent, and lg, for liguleless. The heterozygous F₁ is testcrossed with a homozygous recessive, for all the three genes.

The F₂ progeny is:

• 305 - + v lg

• 275 – b + +

• 128 – b + lg

• 112 - + v +

• 74 - + + lg

• 66 – b v +

• 22 - + + +

• 18 – b v lg

Total: 1000

To determine the gene sequence, compare the most frequent class with the least frequent class [double crossover –DCO]. Since, the middle gene flips with respect to the flanking genes, the gene order can be determined as v b lg.