1. Department of Biology and Center for Molecular Genetics, University of California, San Diego, La Jolla, CA 92093-0116, USA.
2. Department of Anthropology, University of California, San Diego, La Jolla, CA 92093, USA.
3. Center for Demographic and Population Genetics, University of Texas Graduate School of Biomedical Sciences, Houston, TX 77225, USA.
4. Jane Goodall Institute-USA, Ridgefield, CT 06877, USA.