Review articleForeign DNA acquisition by invertebrate genomes

- The acquisition of foreign DNA by invertebrate genomes is more common than originally thought.
- The transferred DNA is of bacterial, eukaryote or viral origin.
- The receiver species may end up utilising the transferred genes for its own benefit.
- Viruses are major players in horizontal gene transfers targeting insect genomes.
- A gene introduced in insects via genome editing might spread to other species.

Recent studies have highlighted that the accidental acquisition of DNA from other species by invertebrate genomes is much more common than originally thought. The transferred DNAs are of bacterial or eukaryote origin and in both cases the receiver species may end up utilising the transferred genes for its own benefit. Frequent contact with prokaryotic DNA from symbiotic endocellular bacteria may predispose invertebrates to incorporate this genetic material into their genomes. Increasing evidence also points to viruses as major players in transferring genes and mobile elements between the species they infect. Unexpectedly a gene flux between Hymenoptera and Lepidoptera mediated by endogenous viruses of parasitic wasps has been recently unravelled, suggesting we are probably just seeing the tip of the iceberg concerning horizontal gene transfers in invertebrates. In the context of insect for feed and food, if the new technology of insect genome editing (such as Crisper/Cas9) were used to modify the genome of reared insects it is important to take into account the risk that an introduced gene can be transferred. More generally, although insects are traditionally consumed in Asia and Africa, knowledge on insect viruses is still limited rendering it difficult to predict the impact they might have in the context of insect rearing at an industrial scale.

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