Wayne, Flynn, and collaborators propose to provide the most detailed examination to date of relationships within the vertebrate order that includes mammalian carnivores such as cats, dogs, weasels, raccoons and seals. This effort represents the first attempt to document the relationship of all species in a moderately diverse mammal order. The researchers will produce a comprehensive relationship tree of several hundred species using DNA sequences of 33 genes that will form the basis for testing ideas about how and when various traits influencing carnivore behavior, ecology and function have evolved and been shaped by natural selection. Additionally, the proposal supports collection of morphologic data on living and extinct carnivores that will be combined with the DNA sequence data to test key ideas about evolutionary history. Along with the public-financed genome sequencing of the dog and partial sequencing of the cat, this study will add a comparative database of carnivore sequence data and provide an evolutionary perspective that will add a new dimension to interpreting the significance of sequence differences in humans and other mammals.
This project includes support for extensive training and inter-institutional exchange of the next generation of systematists, including three post-doctoral scientists, several graduate students and dozens of undergraduates. Further, the consortium of investigators and institutions collaborating in this project (5 universities, two museums, one governmental laboratory, plus international collaborators) are well situated to more deeply immerse K-12 students and teachers, and the general public, in the approaches and results of systematic biology research. Finally, the scientists will develop a multi-layer web site with empirical and analytical information and a traveling museum exhibit using carnivores to illustrate fundamental concepts in systematics.
To document and understand the history of life, emphasis has been placed on resolving the major branches of evolutionary trees such as the relationships among families and orders of mammals. However, some key questions can only be addressed by understanding relationship of all species within smaller groups, such as carnivores (Figure 1). Specifically, questions about how rapidly new species appear and go extinct and the causes of extinction require a focus at the tips of an evolutionary tree. Consequently, comprehensive phylogenies are needed at the species level. Our principal objective for this study was to generate a phylogeny based on an analysis of DNA sequences from 21 nuclear genes of nearly all species in the mammalian order Carnivora. The results of this research would produce a species-level tree of a diverse vertebrate order that will allow past as well as new systematic and evolutionary questions to be addressed. No other diverse mammalian order has ever been sequenced so thoroughly for nearly every species it contains. We also characterized key morphological characters of recent and extinct species to add a critical understanding of how the form and function of organisms evolve and how morphology reveals evolutionary relationships. We also use new methods to date the divergence of key branches in the history of carnivores and correlate these events with changes in the physical and biotic environment. As a result of NSF support, we have accumulated an extensive DNA collection of carnivore species sampling about 95% of living genera and about 80% of species. We are currently sampling museum collections to fill in the remaining missing species. We have published preliminary phylogenetic trees of a reduced set of carnivore species and are preparing for submission a publication involving about half of all living taxa. We have completed morphologic studies of key species and are using the DNA sequenced biased evolutionary tree to understand the pattern and tempo of the appearance of key innovations. Our results show that carnivores have been highly constrained in their evolutionary history by environmental and geological factors but uniquely, in large carnivores, competition and body size have played critical roles in limiting the evolution of competing species. Our carnivore evolutionary tree provides a comprehensive resource for understanding the evolution of carnivores, which in turn, play a primary role in structuring mammalian communities. Finally, our evolutionary analyses have provided new insights into the history of enigmatic taxa, such as the now extinct Falkland island wolf.
