Chapter 14, Problem 4Q

Summary Introduction

To review:

The reason behind the restoration of the wild-type phenotype after the fusion of two mutant strains, assuming that the enzyme required to catalyze a pathway has a quaternary structure.

Given:

The enzyme has a quaternary structure and has the α₂β₂ conformation.

Introduction:

The mutant haploid strains of Neurospora like, Leu-1 and Leu-2, are unable to synthesize leucine because of the lack of enzymes that are required for its synthesis. When two strains are fused together and the diploid organism receives a copy of each enzyme form each parent and is able to restore the wild-type phenotype.