Research progress on horizontal gene transfer and its functions in insects.

Horizontal gene transfer (HGT) refers to the asexual exchange of genetic information between distantly related organisms. Although it is well acknowledged that HGT greatly contributes to the adaptive evolution in prokaryotes, its significance in shaping the orientation of eukaryote evolution remains obscure, especially in insect lineages. The massively expanded genomic data appears to be an excellent choice to uncover the mystery of HGTs in insects nowadays. Here we gather a body of evidence showing the HGT events from three broad donor origins, viruses, prokaryotes, and eukaryotes, in which most horizontally transferred genes are unlikely to be functional and will be eroded as a result of the difference of inheritable background between insect recipients and donor species. Nevertheless, particular interests in the prominent role of insect HGTs in maintaining and acquiring new functionalities have still been raised to underpin their adaptations. Among these, the previously investigated properties including reproduction regulation, detoxification of plant metabolites, formation of body color, and antimicrobic immunity are mainly included in different insect lineages. Albeit such cases are just the tip of the iceberg, we demonstrate that HGT drives insect evolution, especially in coevolution with host plants, and additional explorations into its functions should be given attention in order to access the complex evolutionary history of insects in the near future. [ABSTRACT FROM AUTHOR]