Solar-powered sea slugs defy evolution and horizontal gene transfer

Horizontal gene transfer (HGT) has been proposed as the major explanation for the large number of genes shared among completely unrelated taxon that share no lineage-specific evolutionary trajectory in the schema of life. However, mechanisms to explain HGT between multicellular eukaryotic life are lacking. Initial reports of HGT in a defined biological relationship between the solar-powered sea slug E. chlorotica and its algal prey seemed to provide the key evidence for such a mechanism. However, new data from the germline sequencing of the slug’s genome via the use of eggs as a DNA source has shown that no algal DNA is present—definitively negating HGT in E. chlorotica. The explanation for the original data that seemed to support HGT is now believed to be that it is due to the presence of extra chromosomal circular DNAs (eccDNAs) excized from the algal genome. The nature of how these eccDNAs are formed and utilized in slug cells to help support the maintenance of its stolen algal chloroplasts remains to be deduced. This amazing phenomenon can only be explained within the context of a highly co-designed and biologically complex system inherent to the model of intelligent design.