Estudo de elementos Galluhop e Cr1-like nos genomas de aves

Abstract

Transposable Elements (TEs) are sequences that have the particularity of mobilizing within and between genomes, being ubiquitously present in organisms and distributed throughout the branches of the tree of life. TEs influence host genomes in different ways and play a key role in their evolution. They are classified into two major classes, based on their transposition intermediary: Class I (retrotransposons) transposes via RNA, Class II (transposons) move through DNA. In birds, the knowledge about transposable elements is still very insipient, being restricted to a few genomes sequenced, mainly the one of Gallus gallus. In this work two distinct types of TEs were studied: galluhop - element of Class II, belonging to the superfamily mariner / Tc1, and CR1 - element of Class I, order known as LINE (of the English Long Interspersed Nuclear Element), belonging to the superfamily CR1. The objectives of this work were to characterize the evolutionary history of galluhop homolog sequences found in avian available genomes and also to characterize the chromosomal distribution of CR1-like in genomes of woodpeckers. In the first chapter, through in silico analysis, it was possible to estimate the diversity of copies, the structural and functional characteristics, the discontinuous distribution in the avian line, the description of a new subfamily for the mariner family and to suggest a horizontal transfer event of the galluhop element . We highlight in this approach the first record of a possible horizontal transfer of transposable element between birds, and the new Gallus subfamily restricted, until now, to galluhop elements found in birds. In the second chapter, we show through the FISH technique the chromosomal distribution of the same transposable element, CR1-E-like, in different bird genomes, showing a very different distribution pattern in each genome, even among species of the same genus.