Horizontal Gene Transfer in Metazoa: Examples and Methods

Horizontal gene transfer (HGT) is now widely accepted as an indispensable mechanism in the evolution of microbes, but its contribution in metazoans still raises controversies. This is partly due to the methodologies used for the comprehensive prediction of HGT candidates from genomic information and also because the specific pathways that allow the incorporation of foreign DNA in the germline cells and subsequently to their chromosomes remain elusive. Here, we review the methods for HGT detection and examples of HGT events in two metazoan groups, bdelloid rotifers and tardigrades. Both groups are parthenogenetic and are capable of surviving desiccation (anhydrobiosis), and the roles of these features in promoting HGT, and of HGT loci to these phenomena, are discussed.