An evaluation of the ecological relationship between Drosophila species and their parasitoid wasps as an opportunity for horizontal transposon transfer

Abstract

Evidences of horizontal transfer, the exchange of genetic material between reproductively isolated species, have accumulated over the last decades, including for multicellular eukaryotic organisms. However, the mechanisms and ecological relationships that promote such phenomenon is still poorly known. Host-parasite interaction is one type of relationship usually pointed in the literature that could potentially increase the probability of the horizontal transfer between species, because the species involved in such relationships are generally in close contact. Transposable elements, which are well-known genomic parasites, are DNA entities that tend to be involved in horizontal transfer due to their ability to mobilize between different genomic locations. Using Drosophila species and their parasitoid wasps as a host-parasite model, we evaluated the hypothesis that horizontal transposon transfers (HTTs) are more frequent in this set of species than in species that do not exhibit a close ecological and phylogenetic relationship. For this purpose, we sequenced two sets of species using a metagenomic and single-species genomic sampling approach through next-generation DNA sequencing. The first set was composed of five generalist Drosophila (D. maculifrons, D. bandeirantorum, D. polymorpha, D. mercatorum and D. willistoni) species and their associated parasitoid wasps, whereas the second set was composed of D. incompta, which is a flower specialist species, and its parasitoid wasp. We did not find strong evidence of HTT in the two sets of Drosophila and wasp parasites. However, at least five cases of HTT were observed between the generalist and specialist Drosophila species. Moreover, we detected an HT event involving a Wolbachia lineage between generalist and specialist species, indicating that these endosymbiotic bacteria could play a role as HTT vectors. In summary, our results do not support the hypothesis of prevalent HTT between species with a host-parasite relationship, at least for the studied wasp-Drosophila pairs. Moreover, it suggests that other mechanisms or parasites are involved in promoting HTT between Drosophila species as the Wolbachia endosymbiotic bacteria.

Bacteriophage WO Can Mediate Horizontal Gene Transfer in Endosymbiotic Wolbachia Genomes

“…Abundant evidence of HGT has been detected over the last few decades, particularly in prokaryotic organisms (Ortiz et al, 2015). The genes acquired by HGT can provide new activities to a bacterial host (Waldor and Mekalanos, 1996; Brüssow et al, 2004; Rodriguez-Valera et al, 2009; Modi et al, 2013).…”

Horizontal Transfers and the New Model of TE-Driven Genome Evolution in Eukaryotes

“…Below is a non-exhaustive description of the newest reports from the past year that illustrates the contribution of NGS (Next Generation Sequencing) technologies to the field of evolutionary genomics: Ortiz et al (2015) looked for HTTs among several Drosophila species, together with some parasitic wasp species using a metagenomic approach based on full genome sequencing of several individuals from each species. They identified five HTT between Drosophila species that do not share the same ecological habitat.…”

Risks of Wolbachia mosquito control

“…However, few have focused on the probability of Wolbachia strains being transferred to other insects and the potential environmental and economic impacts of this host shift. Wolbachia strains (including wMel-like strains) are capable of transferring horizontally among distantly related arthropods in a short evolutionary time (6,7). Moreover, some parasites are able to carry Wolbachia strains to other species (6).…”