Análise de diversidade e expressão de retrotransposons ativos em espécies de Coffea

• Autor(a) principal: Dias, Elaine Silva [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/139368
• topic: Genetica molecular; Genoma; Café - Genetica; Plantas - Evolução; Molecular genetics

The evolutionary history of the angiosperms is characterized by its rapid and broad diversification, whose background is due to the action of numerous factors; among them, the transposable elements (TEs) have been considered as one of the most important agents. TEs might compose large portions of the plant genomes, and play an important role in promoting genetic diversity. The aim of this study was to investigate the evolutionary dynamics of active TEs in the Coffea species. In the first chapter, are presented the results of an extensive analysis of the distribution and evolution in plant genomes of a retrotransposon with LTR (LTR-RT), the Copia25. Copia25 is widely distributed in the Rubiaceae family, and is present in distantly related species belonging to the Rosidae and Asteridae subclasses, and the class of monocotyledons. In particular, it was observed an incongruity involving Copia25 sequences of Musa species, a monocot, and Ixora species, a dicot (Rubiaceae), which could be due to horizontal transfer (HT) between these species or their ancestral lineages. Copia25 has a complex evolutionary dynamics in angiosperms, whose history could include conservation sequences, stochastic loss and HT. Ten LTR-RTs were annotated in C. canephora genome and had their insertional profiles obtained, using IRAP and REMAP methods, in genotypes of the parental species, C. canephora and C. eugenioides, and the allotetraploid, C. arabica. Losses of insertions could have occurred in the allotetraploid, these being more significant in five out of ten families studied, and also was observed the occurrence of directional changes in progenitors subgenomes, being more frequent those occurred in maternal subgenome, C. eugenioides. This study contributes to the understanding of the evolution of LTR-RTs within genomes, the colonization of new genomes for these elements as well as its evolutionary dynamics in a newly originated genome