Which types of phenotypic ratios are likely to occur in crosses when dealing with a single gene pair for which all the genotypic combinations are of equal viability?
A) 9:3:3:1, 27:9:9:9:3:3:3:1
B) 1:2:1, 3:1
C) 1:4:6:4:1, 1:1:1:1
D) 12:3:1, 9:7
E) 2:3, 1:2

Question

Quizplus · Accepted Answer

When dealing with a single gene pair for which all the genotypic combinations are of equal viability, the most likely phenotypic ratios are 1:2:1 or 3:1. Option B lists these two ratios, making it the correct answer. Option A lists the ratios for a dihybrid cross, while option C lists ratios for incomplete dominance or co-dominance. Option D lists ratios for a trihybrid cross, and option E lists ratios for sex-linked inheritance.

Which Types of Phenotypic Ratios Are Likely to Occur in Crosses