On chromosome 8 in the low-GC region is a protein located, which has a homology to genes of D. pulex and D. magna. These genes code for the protein septin 7, which is important for the endocytosis-based invasion process of a fungal pathogen. The O. colligata genome has acquired these genes from its Daphnia host by horizontal gene transfer. It is suggested, that the parasite uses the acquired septin to induce its incorporation in a host cell by mimicking host receptors. However, no evidence has been found of the gene retaining its function after the host-to-parasite horizontal gene transfer.
