The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


Quantitative trait variation in purebred baboons and their hybrids

CHANTAL C. ROSSOUW and REBECCA R. ACKERMANN.

Department of Archaeology, University of Cape Town

Thursday All day, Clinch Concourse Add to calendar

Recent genetic studies indicate that contact and admixture occurred amongst contemporaneous hominins (e.g. modern Africans, Neanderthals, Denisovans) as they moved into new environments. However, the phenotypic effects of hybridization remain poorly understood, making it difficult to locate individual hybrids or hybrid zones in the fossil record. A more nuanced understanding of the effects of hybridization will also allow us to better understand the underlying evolutionary processes that have affected our lineage in the past. Here we report on a study of craniometric differences between known pedigree hybrid (n=72) and purebred baboons (P. anubis and P. cynocephalus) (n=461), as well as other baboon species (P. hamadryas (n=44), P. papio (n=28) and P. ursinus (n=220)). The hybrids were analysed in two different groups: (1) F1= P. anubis x P. cynocephalus first generation hybrids; (2) B1= P. anubis x F1 backcross hybrids. Twenty-four (24) craniometric variables were compared. Results show that hybrids differ significantly from the other baboon taxa, including their parent taxa. Moreover, they are more variable morphologically than their parent taxa, with phenotypic variation at the limits of, and sometimes outside of, that seen in either anubis or yellow baboons. This supports previous studies indicating that differences between parent and hybrid baboon populations can be detected in traits affecting cranial morphology, and indicates that hybridization can have a substantial quantitative effect on baboon morphology, causing increased variation as well as transgressive phenotypes.

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