Squirrels as models in macroevolution; scaling

PI(s): V. Louise Roth (Duke University)
Start Date: 1-Oct-2006
End Date: 1-Jul-2008

Squirrels as models of macroevolution:
The squirrel family (Sciuridae) is diverse, morphologically and ecologically disparate, and widespread. Squirrels have been used as model organisms for studies of physiology and behavior and are currently subjects of full-genome sequencing. From the combination of (1) a well-corroborated phylogeny, (2) a molecule that in its pattern of nucleotide substitution has shown exceptional clock-like regularity, and (3) an unusually well preserved and well dated early fossil member of the family, we have found that geography has played a central role in sciurid diversification. Reciprocally, sciurid phylogeny can illuminate both molecular evolution and geographic history. In this way, the evolutionary history of squirrels in a temporal and geographic context is serving as a model for understanding broader issues and for reconstructing the biotic and geographic history of complex regions.
Body size--arguably the most important of traits in its correlation with other morphological, physiological, and ecological attributes--has noteworthy consequences for the evolutionary modification of organismal structure, function, and development. As an additional line of study I am examining the relationship between body size and specific array of other traits within several taxa of mammals in a phylogenetic context.

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