title: Interspecific hybridization as a genomic stressor inducing mobilization of transposable elements inDrosophila.
abstract: Transposable elements (TEs) are DNA sequences able to be mobilized in host genomes. They are currently recognized as the major mutation inducers because of their insertion in the target, their effect on neighboring regions, or their ectopic recombination. A large number of factors including chemical and physical factors as well as intraspecific crosses have traditionally been identified as inducers of transposition. Besides environmental factors, interspecific crosses have also been proposed as promoters of transposition of particular TEs in plants and different animals. Our previous published work includes a genome-wide survey with the set of genomic TEs and shows that interspecific hybridization between the speciesDrosophila buzzatiiandDrosophila koepferaeinduces genomic instability by transposition bursts. A high percentage of this instability corresponds to TEs belonging to classes I and II. The detailed study of three TEs (Osvaldo,Helena, andGalileo), representative of the different TE families, shows an increase of transposition in hybrids compared with parental species, that varies depending on the element. This study suggests ample variation in TE regulation mechanisms and the question is why this variation occurs. Interspecific hybridization is a genomic stressor that disrupts the stability of TEs probably contributing to a relaxation of the mechanisms controlling TEs in theDrosophilagenome. In this commentary paper we will discuss these results and the molecular mechanisms that could explain these increases of transposition rates observed in interspecificDrosophilahybrids.
authors.affiliation: Grup de Biologia Evolutiva; Departament de Genètica i Microbiologia; Facultat de Biociències; Universitat Autònoma de Barcelona; Barcelona, Spain.
authors.forename: Maria Pilar García
authors.initials: MP
authors.lastname: Guerreiro
keywords: Drosophila; epigenetic factors; genomic instability; interspecific hybridization; transposable elements; transposition