Abstract
Hybridization between species is a genomic instability factor involved in increasing mutation rate and new chromosomal rearrangements. Evidence of a relationship between interspecific hybridization and transposable element mobilization has been reported in different organisms, but most studies are usually performed with particular TEs and do not discuss the real effect of hybridization on the whole genome. We have therefore studied whole genome instability of Drosophila interspecific hybrids, looking for the presence of new AFLP markers in hybrids. A high percentage (27–90%) of the instability markers detected corresponds to TEs belonging to classes I and II. Moreover, three transposable elements (Osvaldo, Helena and Galileo) representative of different families, showed an overall increase of transposition rate in hybrids compared to parental species. This research confirms the hypothesis that hybridization induces genomic instability by transposition bursts and suggests that genomic stress by transposition could contribute to a relaxation of mechanisms controlling TEs in the Drosophila genome.
Highlights
Natural hybridization is a well known phenomenon in organisms living in sympatry and constitutes an important mechanism of speciation [1,2]
One of the most evaluated consequences of hybridization is that the merging of two different genomes triggers a ‘‘genomic shock’’ leading to genomic modifications including cascades of new gene expressions often accompanied by transposable element (TE) mobilizations [7]
AFLP instability markers were selected in 3 backcross generations of hybrids (BC1, backcrosses 2 (BC2), BC3) and in segmental hybrids between D. buzzatii and D. koepferae
Summary
Natural hybridization is a well known phenomenon in organisms living in sympatry and constitutes an important mechanism of speciation [1,2]. In Drosophila, interspecific hybrids have given sometimes different results; while interspecific hybrids between species from the melanogaster subgroup [26] and affinis [27] subgroup do not have an increased transposition rate, two well described examples of TEs activation associated to interspecific hybridization are known. In response to genomic stresses, TE mobilization is a universal response for all genomic TEs or, on the contrary, it depends on the kind of element If this were the case, it would explain why no TE mobilization was found in other Drosophila species. We undertook a genome-wide dissection of TE mobilization in Drosophila interspecific hybrids, including a quantitative estimation of transposition rates of some TEs. Knowledge of the impact of hybridization in TE activation is a prerequisite for understanding the implication of TEs in reproductive isolation, speciation and, eventually, in the evolution of hybrid lineages
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
