Single-cell parasites co-opt “ready-made” genes from host

Ottawa, ON — Two species of single-cell parasites have co-opted “ready-made” genes from their hosts that in turn help them exploit their hosts, according to a new study by University of Ottawa and University of British Columbia researchers.

Part of a group of parasitic microbes commonly found in the intestines of vertebrates they are called microsporidia, Encephalitozoon hellem and Encephalitozoon romaleae and are related to fungi. In humans, they are associated with people with immune deficiencies.

The research team identified six genes in these parasites that were not found in any other microsporidian. Rather than slowly inheriting individual genes, E. hellem and E. romaleae have acquired a suite of genes from their hosts that produce folate, a form of folic acid that helps cell division and growth.

“The discovery of these genes underpins the surprising capacity of even the most reduced parasites genomes to rapidly improve their metabolism by acquiring several genes that build-up new pathways, perhaps allowing them to quickly adapt to new hosts,” says Nicolas Corradi, Assistant Professor, Department of Biology, University of Ottawa.

Details are published this week in the online journal PNAS Early Edition.