Research Program
Hidden in the features of Nature's creations is a living-record of the great unfolding of life on Earth. Despite their different uses, the limbs of bats, birds, humans, and even whales are built from the same constitutive parts. The 'same' features in different organisms despite their different uses are called homologies. While homology is well known as the basis of taxonomic classification, its existence on a larger scale is manifested as the variations-on-a-theme diversity readily apparent in animals, plants and fungi. This regular pattern in organisms due to common descent makes it possible to study animals and plants to learn about human biology.
At the same time, different parts of animals - and hence different parts of their genomes - evolve at radically different rates. Some genes evolve extremely quickly, for example, genes with immune-related functions (Castillo-Davis and Kulathinal et al. 2004). Other genes evolve extremely slowly or not at all, for example genes involved in basic cellular functions like protein synthesis and mRNA splicing (Castillo-Davis and Kulathinal et al. 2004). Gene duplication, cis-regulatory evolution, and even intron gain and loss appear to behave equally capriciously in their evolutionary dynamics (Castillo-Davis and Hartl 2002; Castillo-Davis et al. 2004b; Castillo-Davis, Bedford, Hartl 2004c).
Since the rate of change of different animal features is so heterogeneous and seemingly complex, it would be useful to discover a set of general genetic rules to explain and predict why particular morphological, physiological, and molecular features are conserved between species whereas others are not. The discovery of evolutionary genetic rules that result in "phenotypic inertia" is a central research goal of our lab.