Despite its central relevance for organismal biology and biomedicine, surprisingly little is known about the evolutionary history of the brain. A primary goal of the lab is to quantify neuroanatomical features (such as volumetrics, cortical layer thickness, cell density) across species and use phylogenetic comparative methods to infer the evolutionary changes that have occurred on individual branches of the tree of life. These approaches allow identifying which neural changes characterize individual species, when in evolutionary history major shifts in brain organization occurred, which brain systems have been under particular selective pressure, and what the mechanisms are by which natural selection shapes neural diversity across species.
2019. Smaers JB & Vanier DR. Brain size expansion in primates and humans is explained by a selective modular expansion of the cortico-cerebellar system. Cortex, 118: 154-164.
2018. Smaers JB, Turner AH, Gómez-Robles A, & Sherwood CC. A cerebellar substrate for cognition evolved multiple times independently in mammals. eLife 7, e35696.
2017. Smaers JB, Gómez-Robles A, Parks A & Sherwood CC. Exceptional evolutionary expansion of the prefrontal cortex in great apes and humans. Current Biology 27, 714-720.
2013. Smaers J.B., Soligo C. Brain reorganization, not relative brain size, primarily characterizes anthropoid brain evolution. Proceedings of the Royal Society B-Biological Sciences 280, 20130269.
Skeletal morphological evolution has long been viewed as one of a clear form-function relationship involving gradual adaptation to specific biota. Recent developments in phylogenetic comparative methodology allow for more detailed analyses of the evolutionary history of the skeletal system. A core focus of the lab within macroevolutionary morphology is to increase the resolution of phylogenetic inference of cranial and postcranial evolution in order to contextualize the fossil record and detail the balance between modularity and integration across phylogenetic space.
2015. Almécija S, Smaers JB & Jungers WL. The evolution of human and ape hand proportions. Nature Communications. 6:7717.
2014. Goswami A., Smaers J.B., Soligo C. & Polly P.D. The macroevolutionary consequences of phenotypic integration: from development to deep time. Philosophical Transactions of the Royal Society B, 369, 20130254.
Phylogenetic comparative methodology
Phylogenetic comparative methods consider the genetic relatedness between species (summarized as a phylogenetic tree) to infer scaling trends between traits, co-evolutionary patterns among traits and/or detailed evolutionary patterns of change across individual lineages. The lab develops phylogenetic comparative approaches that allow inferring ancestral states, variable rates of change across individual lineages, trait co-evolution, and mechanisms of change across evolutionary time.
2016. Smaers JB & Rohlf FJ. Testing species’ deviations from allometric predictions using the phylogenetic regression. Evolution. 70 (5): 1145-1149.
2016. Smaers JB, Mongle CS, Kandler A. A multiple variance Brownian motion framework for estimating variable rates and inferring ancestral states. Biological Journal of the Linnean Society. 118 (1): 78-94.