Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary
Friday 5:15-5:30, Galleria South
Among primates, hominoids show considerable interspecific variation in limb bone length, both in terms of intra- and intermembral proportions, and also in relation to body size. These differences are thought to have evolved in response to selective pressures relating to different locomotor behaviors. However, the genetic and developmental mechanisms that made this interspecific variation possible in the first place remain largely unknown. Here I present preliminary data from an ongoing artificial selection experiment in mice, designed to address the developmental and genetic basis of skeletal variation in vertebrates. In this experiment, two lines of CD1 mice are selectively bred for increases in relative tibia length, and matched against a control line. The objective is to produce a population of mice in which artificially introduced differences in tibia length can be traced back to their developmental and genetic underpinnings, while permitting in vivo observations of skeletal evolution. Preliminary results from three generations of selection indicate a relatively high heritability of tibia length, leading to a response to selection of ~1.5% tibia length per generation. Developmental and genetic analyses will begin by generation F8, providing for the first time an opportunity to deconstruct a quantitative trait from phenotype to developmental process(es) to genotype. Applications of this unique vertebrate model for understanding the evolution of derived limb proportions of humans and early hominins are also discussed.
This work was supported in part by a Killam Postdoctoral Fellowship, by the Natural Sciences and Engineering Research Council of Canada, and by the Faculty of Veterinary Medicine, University of Calgary