Figure 5: Horizontal transfer of two essential invasion genes.

(a) Identification of an 8 kb transferred segment on chromosome 4. Inter-species distances (colour coded) are shown for syntenic orthologs of P. falciparum, P. reichenowi and P. gaboni. Four genes, including the essential invasion genes CyRPA and RH5, exhibit an unusually high P. falciparum–P. reichenowi (yellow) and an unusually low P. falciparum–P. gaboni (aqua) distance, respectively. Genes are ordered by chromosomal location. Since RH4 is absent from P. gaboni (see Supplementary Fig. 4), only the P. falciparum–P. reichenowi distance is shown. (b,c) Phylogenetic relationships of Laverania RH5 and EBA165 sequences, revealing an unexpectedly close relationship between the P. praefalciparum/P. falciparum lineage and the P. adleri lineage in RH5. Laverania parasites are colour coded according to their host species (chimpanzee, red; gorilla, green; human, black). Trees were inferred by maximum likelihood methods⁶⁹. Numbers at internal nodes represent bootstrap support values (only numbers >80% are shown). Scale bar, 0.02 substitutions per site (additional phylogenies are shown in Supplementary Fig. 9). (d) Schematic diagram of the horizontal transfer region on chromosome 4 in P. reichenowi CDC (top), P. falciparum 3D7 (middle) and P. gaboni SY75 (bottom). Genes are shown in blue; grey bars and broken lines indicate genome gaps (numbering is relative to the first base of chromosome 4). A green line indicates the location of the transferred segment in P. falciparum, with the broken part indicating that the 3′-break point is unclear. The region surrounding the 5′-break point is highlighted by a red box and shown in greater detail in Supplementary Fig. 10.