Figure 1

Phylogenetic relationships of our cohort. We provide a simplified overview of the phylogenies of the species examined in this study along with the inferred age of the last common ancestors at different branch points [8, 9]. The present day is indicated by the light blue dotted line and the human lineage is highlighted in red. Ppy = Pongo pygmaeus (orangutan), Ppa = Pan panisicus (bonobo), Ptr = Pan troglodytes, Hsa = Homo sapiens (human), and Ggo = Gorilla gorilla (gorilla). Although we recognize the close relationships among all five species, we use the term 'great apes' in reference to chimpanzees, bonobos, gorillas, and orangutans.