Kate McGrath, Amandine B. Eriksen, Daniel García-Martínez, Jordi Galbany, Aida Gómez-Robles, Jason S. Massey, Lawrence M. Fatica, Halszka Glowacka, Keely Arbenz-Smith, Richard Muvunyi, Tara S. Stoinski, Michael R. Cranfield, Kirsten Gilardi, Chantal Shalukoma, Emmanuel de Merode, Emmanuel Gilissen, Matthew W. Tocheri, Shannon C. McFarlin, and Yann Heuzé have published "Facial asymmetry tracks genetic diversity among Gorilla subspecies" in the Proceedings of the Royal Society B.

Mountain gorillas are particularly inbred compared to other gorillas and even the most inbred human populations. As mountain gorilla skeletal material accumulated during the 1970s, researchers noted their pronounced facial asymmetry and hypothesized that it reflects a population-wide chewing side preference. However, asymmetry has also been linked to environmental and genetic stress in experimental models.

Facial asymmetry correlates neither with tooth wear asymmetry nor increases with age in a mountain gorilla subsample, undermining the hypothesis that facial asymmetry is driven by chewing side preference. An examination of temporal trends shows that stress-induced developmental instability has increased over the last 100 years in these endangered apes.

Arbenz-Smith, an administrative assistant in the Department of Small Animal Clinical Sciences, performed the histology/sample prep and image analysis for this paper.