Chapter 12, Problem 15P

Summary Introduction

a.

To determine:

The genotype and phenotype of haploid spores formed by a single crossover outside the inverted region.

Introduction:

The mating between the two strains $\left(\text{ura3/arg9}\times \text{URA3/ARG9}\right)$ resulted in the production of a diploid strain, which was ura3/arg9; URA3/ARG9.

Summary Introduction

b.

To determine:

The genotype and phenotype of haploid spores formed by a single crossover between URA3 and centromere.

Introduction:

A single crossover between URA3 and centromere will result in the displacement of ura3 and URA3 genetic markers.

Summary Introduction

c.

To determine:

The genotype and phenotype of haploid spores formed by a double crossover that involves same two chromatids each time.

Introduction:

In the case of double crossover, the first crossover between URA3 and centromere will displace ura3 and URA3. The second crossover that occurred between ARG9 and arg9 will displace arg9 and ARG9.