Tesis doctoral de M Mar Marzo Llorca
Transposable elements (te) are repetitive sequences whose defining characteristic is its ability to change their location in the genome. They made up a important proportion of the eukaryotic genomes, and although they are often considered as genetic parasites, it has been also argued that they might have some still unknown cellular function. Nevertheless, it is clear that they play a role as drivers of their host evolution, due to the fact that tes generate genetic variability. the te galileo is involved in the generation of adaptive chromosomal rearrangements in natural populations of drosophila buzzatii, indicating that it would be a driver of adaptation in its host. Moreover, all galileo elements found in previous works were incomplete – mainly composed by foldback-like structures – and homology relationships could not be established with any known sequence. With this background, this thesis was proposed to characterise the mobile genetic element galileo in different drosophila species and analyse its evolutionary dynamics. Thus, in a first phase we searched for complete copies of galileo in different species of the drosophila genus: d. Buzzatii, d. Mojavensis, d. Virilis, d. Willitoni, d. Ananassae, d. Pseudoobscura and d. Persimilis, using both bioinformatic and experimental methods (depending on whether the analysed genome was available or not). The copies found present long tir (up to 1.2 kb), high sequence identity with previously found galileo sequences and, moreover, they harbour coding sequences that have allowed the classification of galileo as a member of the p-element superfamily. Subsequently, by means of phylogenetic analyses, we have found that there are galileo subfamilies in three different species (d. Buzzatii, d. Mojavensis, d. Virilis) and evidence of recent transpositional activity (in d. Willitoni, d. Ananassae, d. Pseudoobscura, d. Persimilis and d. Mojavensis). In a second phase of the thesis, we have conducted experiments with part of the galileo protein and detected specific binding to the galileo tir, confirming that this sequence is responsible for the transposition reaction. Finally, we have thoroughly studied the galileo variability in the d. Mojavensis genome and found a striking structural variation, suggesting that the exchange of sequences among different galileo copies might be quite common and important for tes evolution.
Datos académicos de la tesis doctoral «The transposon galileo in the drosophila genus«
- Título de la tesis: The transposon galileo in the drosophila genus
- Autor: M Mar Marzo Llorca
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 14/12/2011
Dirección y tribunal
- Director de la tesis
- Alfredo Ruiz Panadero
- Tribunal
- Presidente del tribunal: pierre Capy
- Elena Casacuberta (vocal)
- (vocal)
- (vocal)