Chapter 8.4, Problem 42AQP

Summary Introduction

To explain:

The origin of F₂ plants obtained by R.E. Clausen and T.H. Goodspeed and the number of chromosomes observed during metaphase I and metaphase II.

Introduction:

There are two species of Nicotiana, namely- Nicotiana glutinosa$\left(\text{2n}=\text{24}\right)$ and Nicotiana tabacum$\left(\text{2n}=48\right)$ which can be intercrossed; however, the F₁ progeny are sterile. During the experiment conducted by R.E. Clausen and T.H. Goodspeed, they obtained one fertile F₁ plant. The F₂ progeny obtained after self-crossing were also fertile and on examination, it was found that the number of chromosomes in the metaphase I was $36$ pairs of homologous chromosomes and number of chromosomes in metaphase II were $36$ individual chromosomes.