speciation

Caswell JL, Mallick S, Richter DJ, Neubauer J, Schirmer C, Gnerre S & Reich D 2008 Analysis of chimpanzee history based on genome sequence alignments. PLoS Genet 4:e1000057.

• bonobos and common chimpanzees were separated ~1,290,000 years ago
• western and other common chimpanzees ~510,000 years ago
• eastern and central chimpanzees at least 50,000 years ago
• the central chimpanzee population size increased by at least a factor of 4 since its separation from western chimpanzees
• while the western chimpanzee effective population size decreased
• in about one percent of the genome, the genetic relationships between humans, chimpanzees, and bonobos appear to be different from the species relationships

• we assumed 7 Mya for human-chimpanzee genetic divergence and 20 years per generation