Fig. 5

Phylogenetic trees marking key moments in the evolution of the var gene family. A The evolutionary relationships of the Laverania are shown, with each parasite species and its ape host denoted. var genes, the regulatory intronic element and the putative regulatory protein PTEF are thought to have originated in the common ancestor of the entire subgenus (shown by green asterisk). A significant shift in the structure of the var encoded protein EMP1 and the UpsC upstream regulatory type occurred in the common ancestor of the bottom five species (shown by red asterisk) while the evolution of the conserved genes var1csa and var2csa, as well as the UpsA and B types, occurred prior to the branch that includes the human parasite P. falciparum (shown by purple asterisk). B The codivergence model of parasite speciation is displayed showing the branch of the Laverania that evolved var1csa, var2csa and the UpsA/B/C organization. The phylogenetic tree shows the evolution of gorillas, humans, chimpanzees and bonobos from a common ancestor ~ 8–9 million years ago. This model presumes that parasites species diverged along with their hosts, resulting in P. praefalciparum, P. reichenowi and P. lomamiensis infecting gorillas, chimpanzees and bonobos, respectively. Humans are hypothesized to have lost their original parasites, then become reinfected through a recent gorilla-to-human transmission event, resulting in P. falciparum. These ape species (and their parasites) initially diverged during the late Miocene, a period of major climatic change in Africa marked by aridification and a regional shift from rainforests to grasslands and savannah