**Molecular Basis of Meiosis**

sis theory. By this theory, meiosis is derived from the processes by which a postulated viral

The last chapter of the book presents a practical approach to teaching meiosis and gives ex‐ amples of how a low cost program can be set up. This program will allow students to under‐ stand the general processes employed by different types of plants that undergo meiosis. It emphasizes gross morphology and aspects of morphology that can be observed with a hand

**Carol Bernstein and Harris Bernstein**

University of Arizona, USA

Department of Cellular and Molecular Medicine

ancestor of the nucleus infected new hosts.

lens or under a microscope.

VIII Preface

**Chapter 1**

**Intrinsic Homology-Sensing and Assembling Property of**

The first meiotic prophase is divided into five sequential stages, referred to as *leptotene, zygotene, pachytene, diplotene* and *diakinesis*. Chromosome pairing is initiated during the late *leptotene* and early *zygotene*. As the stage progresses, the four chromatids are arranged and form two distinct pairs of sister chromatids, and the two chromatids in each pair are tightly aligned along their entire lengths. The synaptonemal complex (SC) is fully formed at the *pachytene* stage. Although such morphological changes in chromosomes and the mechanism of recombination have been well studied, we do not still understand how each chromosome recognizes and approaches its matching mate or homologue and the mechanism by which it interacts and pairs with its homologue. Regarding the latter phenomenon, double-stranded (ds) DNA has long been considered to have the ability to distinguish self and non-self. Indeed, this property of DNA was predicted about 60 years ago (Jehle, 1950; Yos *et al.*, 1957) and was directly demonstrated a half-decade ago, when dsDNA molecules were proved to have sequence-sensing and self-assembly properties (Inoue *et al*., 2007). In the following two years, other studies describing the presence of such properties in DNA were reported (Baldwin *et al*., 2008; Danilowicz *et al*., 2009). A more recent study has revealed that nucleosomes retain this DNA sensing property and can self-assemble (Nishikawa and Ohyama, 2013). In this chapter, we define the self-association of the same dsDNA molecules as DNA self-assembly and that of nucleosomes with identical DNA as nucleosome self-assembly. And, we will discuss the recent findings on DNA self-assembly and nucleosome self-assembly and their

relationships, as putatively significant mechanisms in the early stage in meiosis.

and reproduction in any medium, provided the original work is properly cited.

© 2013 Nishikawa et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

**Chromatin Fiber**

http://dx.doi.org/10.5772/56548

Takashi Ohyama

**1. Introduction**

Jun-ichi Nishikawa, Yasutoshi Shimooka and

Additional information is available at the end of the chapter

**Chapter 1**
