Abstract
BackgroundThe presence of transposable elements (TEs) in genomes is known to explain in part the variations of genome sizes among eukaryotes. Even among closely related species, the variation of TE amount may be striking, as for example between the two sibling species, Drosophila melanogaster and D. simulans. However, not much is known concerning the TE content and dynamics among other Drosophila species. The sequencing of several Drosophila genomes, covering the two subgenus Sophophora and Drosophila, revealed a large variation of the repeat content among these species but no much information is known concerning their precise TE content. The identification of some consensus sequences of TEs from the various sequenced Drosophila species allowed to get an idea concerning their variety in term of diversity of superfamilies but the used classification remains very elusive and ambiguous.ResultsWe choose to focus on LTR-retrotransposons because they represent the most widely represented class of TEs in the Drosophila genomes. In this work, we describe for the first time the phylogenetic relationship of each LTR-retrotransposon family described in 20 Drosophila species, compute their proportion in their respective genomes and identify several new cases of horizontal transfers.ConclusionAll these results allow us to have a clearer view on the evolutionary history of LTR retrotransposons among Drosophila that seems to be mainly driven by vertical transmissions although the implications of horizontal transfers, losses and intra-specific diversification are clearly also at play.
Highlights
The presence of transposable elements (TEs) in genomes is known to explain in part the variations of genome sizes among eukaryotes
Along with losses and intra-specific diversity, seem to be the most common scenario to explain the phylogenetic pictures we observed, we identified some new cases of horizontal transfer (HT) especially among certain species from the melanogaster subgroup and detected some new groups of TEs that are absent from D. melanogaster, D. simulans, D. sechellia, and D. erecta
This could be due to the fact that in D. melanogaster, the TEs correspond to mainly full-length elements whereas in the other species full-length elements are more rare, as it has been observed when analyzing 12 Long terminal repeat (LTR)-retrotransposons [6]
Summary
The presence of transposable elements (TEs) in genomes is known to explain in part the variations of genome sizes among eukaryotes. Even among closely related species, the variation of TE amount may be striking, as for example between the two sibling species, Drosophila melanogaster and D. simulans. The sequencing of several Drosophila genomes, covering the two subgenus Sophophora and Drosophila, revealed a large variation of the repeat content among these species but no much information is known concerning their precise TE content. The identification of some consensus sequences of TEs from the various sequenced Drosophila species allowed to get an idea concerning their variety in term of diversity of superfamilies but the used classification remains very elusive and ambiguous. Even among closely related species, the variation of TE amount may be striking, as it is the case for the two sibling species, Drosophila melanogaster and D. simulans. From the name and annotation, it is not possible to tell the difference between the LTR-retrotransposons BEL1 and BEL-1 from D. virilis nor it is possible to consider that the element Gypsy-1 present in D. rhopaloa is homologous to the element Gypsy-1 in D. ficusphila
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.
