First fossil chimpanzee

The chimpanzee genome The cover photo by Kevin Langergraber shows the adult female chimpanzee ‘Jolie’ in Kibale National Park, Uganda. This was taken on 16 August 2004, a few weeks before Jolie gave birth to her first infant. This week marks a landmark in the study of our closest living relative: the publication by the Chimpanzee Sequencing and Analysis Consortium of the initial sequence of the chimpanzee genome, together with a comparison with the human genome. The paper describes changes that have shaped human and chimpanzee species since the split from our common ancestor, and hints at what makes us uniquely human: 35 million single-nucleotide substitutions, 5 million small insertions and deletions, local rearrangements and a chromosome fusion. A comparison of gene duplications in chimpanzee and human genomes reveals gene expression differences that may underlie disease susceptibility. A study of primate genomes shows that subtelomeres are hot spots of recent chromosomal duplication and gene conversion. Conservation of Y-linked genes during human evolution is revealed by comparative sequencing in the chimpanzee. The final research paper in this collection fills a big gap in our knowledge: the first chimpanzee fossils ever found show that chimps and early humans inhabited the same environments in which they evolved and diverged. The fossils — three teeth — are from half-million-year-old sediments in Kenya that also yielded fossils of Homo. Four Progress reviews accompany these papers, looking at chimp culture, social behaviour, psychology and cognition. Elsewhere in the issue, researchers talk about working with chimpanzees, a feature summarizes other primate genome projects, and in two Commentaries, important ethical issues surrounding research on great apes are considered.