The laboratory studies the genetic basis by which form and structure are regulated, both during embryonic development to produce the exquisite morphology of the vertebrate embryo and over evolutionary time to generate the extraordinary and beautiful diversity of animal forms on this planet. In our developmental studies we combine classical methods of experimental embryology with modern molecular, imaging, genetic and genomic techniques for interrogating and testing gene function. In our evolutionary work we have addressed question of morphological, behavioral and metabolic evolution in a variety of species using both developmental and genetic approaches.

Limb development and skeletal morphogenesis

The vertebrate limb is a classical model for understanding patterning and morphogenesis of the embryo. We have a variety of projects using both the chick and mouse systems to address a range of questions, currently including the identification of the transcription factors that specify the early limb bud mesenchyme, the epigenetic regulation of patterning genes that organize the limb bud, and the processes that specify muscles in the correct locations in the limb. We also have a major effort to understand the patterning of the skeletal tissues, including projects on how and why joints form where they do, and how differential hypertrophy of chondrocytes leads to the distinct sizes of the different skeletal elements.

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Physical forces in gut development

There is an increasing appreciation for the role of physical forces in orchestrating aspects of development. We have been focusing on the chick midgut, where we have uncovered roles for physical forces in coiling as well as in villus formation and stem cell localization. Current efforts address how the gut tube first forms from a flat epithelial sheet of cells, how differences in tissue properties alter forces to achieve unique properties of the fore, mid and hind gut, and the control of the differentiation of smooth muscle, a key component in the system that generates physical forces within the developing gut. These studies utilize physical force measurements and modeling approaches in addition to embryological manipulations.

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Metabolic and behavior evolution in cave fish

One of the evolutionary systems we currently use involves the comparison of fish adapted to life in caves with their free-swimming river cousins, with whom they are still inter-fertile. Genetics crosses allow us to map the inheritance of cave-specific traits, and as there are multiple caves that have been independently invaded by the same species, we can study the extent to which the same genes are utilized when selecting for the same traits. Currently we are looking at cave specific feeding behavior and metabolic adaptation to starvation conditions in the caves in addition to morphological traits.

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Insights into the evolution of human-specific traits

Morphologically we are quite different from our nearest cousins, the great apes. We are investigating the genetic basis for a number of human-specific characters, including our unusual skin (miniaturized hair follicles and expansive sweat glands which together allow efficient theromoregulation through perspiring), diminution of our teeth, shortening of our face and decrease in the length of our fingers.

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