Hybrids are the offspring of two different species or varieties of a plant or animal. Recent genetic evidence suggesting that our hominin ancestors interbred with other hominin groups has highlighted hybridization in our own evolutionary past. If there are predictable patterns in hybrid skeletons and teeth, it might be possible to identify evidence of hybrids in the hominin fossil record, for which genetic data cannot always be recovered. A good way to determine whether such patterns exist is to study hybrid skeletal shape in species that are closely related to humans. This project will provide comparative data on hybridization in a colony of macaques (monkeys) that is no longer being expanded and is therefore declining in size as individual animals die. Importantly, because hybridization between Indian and Chinese macaques has occurred in this colony over multiple generations, animals vary from those having high genetic contributions from both of the founding varieties to those with only small genetic contributions from one of the varieties. Hominin hybrids are likely to have had a small genetic contribution from a second hominin species. The data collected and the insights gained in this project will be relevant across multiple fields, including anthropology, primatology, biology, zoology, and quantitative genetics. The study will also support international collaborations and postdoctoral and student mentoring and training.
Recent evidence of gene flow among archaic human lineages (Neandertals, Denisovans, Homo sapiens) has brought admixture to the forefront of anthropological and public interest. This study will develop principled criteria for detecting phenotypic evidence of admixture, using a model organism that is closely related to humans. Skeletal and dental measurements will be collected for approximately 260 macaques from the California National Primate Research Center. The study will quantify and model hybrid phenotypic variation, evaluate how accurately hybrids can be identified and their admixture proportions estimated from phenotypic data, and develop strategies for detecting hybridization in other taxa. Large, genotyped primate samples of known pedigree are very rare. The skeletal sample and associated data will be curated at the University of California, Davis, and made available to other researchers, extending utility of the sample to generations of scientists.
