The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

Mouse models for identifying hybridization in the hominin fossil record: preliminary results


1Department of Archaeology, University of Cape Town, 2Department of Cell Biology and Anatomy, University of Calgary

March 28, 2015 3:45, Ballpark 1/2 Add to calendar

Hybridization has played an important role in structuring genetic and phenotypic diversity across myriad organisms, including primates. While it is often overlooked as a primary agent in hominin evolution more broadly, the sequencing of the Neanderthal and Denisovan genomes has led to increased acceptance that hybridization occurred between geographically and morphologically distinct later hominins. Although recent research on the phenotypic expression of hybridization has provided important insight into our understanding of variation in the hybrid skeleton, our ability to detect hybrids in the fossil record (and therefore the precise time and place of hybridization) is still limited. Here we use a mouse model to better quantify the range of cranial variation within different hybrid samples, and to examine differences in hybrid phenotypes across these samples. We focus on the house mouse, comparing different subspecific (e.g. Mus musculus musculus X M.m. domesticus) and specific (M. musculus X M. spretus) crosses, as well as different types of hybrids (e.g. F1, B1) within each cross. Mice are bred in captivity (N=50/cross). ┬ÁCT scans are acquired from these mice following sacrifice, and analysed in Avizo. Preliminary results indicate that hybrid crania are typically extreme in size relative to their parental taxa, and are highly variable in shape, with many individuals outside of the range of parental variation. We also observe maternal effects in some crosses. This study provides important evidence for the prevalence of heterotic and transgressive phenotypes, and illuminates key differences in the expression of these phenotypes, across hybrid groups.

This project was funded by the National Research Foundation and the NRF-DST Centre of Excellence in Palaeosciences, South Africa