Carey Krajewski

Department of Zoology
Southern Illinois University Carbondale

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Research Interests

I am primarily interested in the application of DNA sequence data to phylogeny reconstruction for avian and mammalian groups. Recently, this research has focused on problems of analyzing multigene data sets using parsimony and model-based methods (additive distances and maximum likelihood). My approach has been to characterize the evolutionary dynamics of specific sequence partitions (e.g., codon positions in protein-coding genes, stems and loops in RNA genes, functional domains) by estimating parameter-values for appropriate substitution models, then integrating this information across partitions to obtain an estimated tree. Understanding how the accuracy and precision of this estimate are affected by heterogeneity among partitions is a significant aspect of the research, as is exploration of recent methods of incorporating model variation among partitions.

Molecular Systematics of Dasyuromorphian Marsupials


"The eastern quoll (Dasyurus viverrinus), a dasyurid marsupial from Tasmania"

Members of the marsupial order Dasyuromorphia are the dominant terrestrial carnivores and insectivores of Australia and New Guinea. Dasyuromorphians include the recently extinct Tasmanian wolf (Thylacinidae), numbats (Myrmecobiidae), and dasyurids (Dasyuridae). The approximately 70 species in this group are found in virtually all Australasian habitats, from high-elevation rainforests to the arid interior. My ongoing collaboration with Dr. Michael Westerman of La Trobe University in Melbourne focuses on reconstructing the phylogeny of all species using DNA sequences. Our current data set encompasses sequences of the mitochondrial cytochrome b, 12S rRNA, 16S rRNA, and control region loci, as well as the nuclear protamine P1, IRBP, and beta-fibrinogen intron 7 loci. Collateral projects include paleobiological and phylogeographic questions and a comparative analysis of the evolution of dasyurid reproductive strategies. Related studies with collaborator Mark S. Springer of UC-Riverside focus on interordinal relationships of marsupials.

Molecular Phylogeny and Evolution of Cranes and Limpkins

"Siberian cranes (Grus leucogeranus) from Asia"

The 15 living species of cranes comprise the avian family Gruidae, the closest living relative of which is the Limpkin (Aramidae). Cranes or limpkins are found on all continents except Antarctica, and most species are threatened or endangered. Collaboration with the International Crane Foundation has provided DNA samples from hundreds of cranes representing all species and many subspecies. Our data set now consists of complete mitochondrial DNA sequences, as well as a 1 kb intron from the nuclear beta-fibrinogen gene, from all cranes. Well-established relationships among crane species are being used as a framework for studying the molecular evolution of these sequences and the performance of model-based inference procedures. We are also pursuing phylogeographic studies of cranes in collaboration with Dr. Judith Rhymer of the University of Maine, and studies of gruiform interfamilial relationships with Dr. Peter Houde of New Mexico State University.

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* SIUC Department of Zoology

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