The molecular biology of apomixis
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biology
presentation
published 11/11/2008
review : Completed
level : Advanced
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Apomixis is the subject of a number of recent reviews. Some authors have focused on the potential agronomic and economic benefits of apomixes. Others have discussed the developmental and genetic basis of apomixes or reviewed current theory regarding the evolutionary and ecological implications of the trait. This text provides a general overview of the field of apomixis research, with an emphasis on our current understanding of the genetic mechanism(s) that underlie its expression in flowering plants, and a sketch of the strategies being taken to introduce this characteristic into crop species. Apomixis is the asexual structure of seeds, avoiding the processes of meiotic decrease and recombination at fertilization, and leading to the formation of genetically uniform progeny. The term apomixis was first coined by Winkler (1908) to describe substitution of sexual reproduction by an asexual multiplication process without nucleus or cell fusion. This is a broad definition that can be interpreted to contain all forms of asexual reproduction.
Table of Contents
- .Introduction
- What apomixis is and where it is found.
- The asexual structure of seeds.
- The distribution of the trait.
- Asexual reproduction in animals.
- The widespread distribution of apomixis amongst flowering plants.
- Apomixis in agriculture.
- Apomixis and the structure of large genetically uniform populations.
- The mechanisms of apomixis.
- Definition.
- Two main mechanisms.
- The structure of an endosperm.
- The detection and measurement of apomixis.
- Detection through the structure of maternal' progeny.
- The need to base any quantitative study of apomixis on a reliable and sensitive method of detecting the trait.
- Flow cytometry.
- The identification of apomixis genes?.
- The finding that gametophytic apomixis was often simply inherited.
- The Synthesis' of apomixis.
- Conclusion.
