Ancient introgression between two ape malaria parasite species

The Laverania clade comprises the human malaria parasite Plasmodium falciparum as well as at least seven additional parasite species that infect wild African apes. A recent analysis of Laverania genome sequences (Otto TD, et al. 2018. Genomes of all known members of a Plasmodium subgenus reveal paths to virulent human malaria. Nat Microbiol. 3:687-697) reported three instances of inter-species gene transfer, one of which had previously been described. Generating gene sequences from additional ape parasites and re-examining sequencing reads generated in the Otto et al. study, we identified one of the newly described gene transfers as an assembly artefact of sequences derived from a sample co-infected by two parasite species. The second gene transfer between ancestors of two divergent chimpanzee parasite lineages was confirmed, but involved a much larger number of genes than originally described, many of which encode exported proteins that remodel, or bind to, erythrocytes. Because successful hybridisation between Laverania species is very rare, it will be important to determine to what extent these gene transfers have shaped their host interactions.