Much of my research revolves around answering the question ‘How do hybridization and introgression affect lineage diversification?’ To answer this question I rely on several morphological and genetic techniques to estimate diversity, phylogenetic relationships, and gene flow. Genetic introgression occurs in many organismal clades, but the extent of introgression in more inclusive lineages is poorly documented. Much less is known about macro-evolutionary patterns in systems with introgressed lineages. Because there are many variables acting to change diversification rates that may act in concert with or completely separate from introgression, e.g., geologic and climatic changes, my research also involves describing these patterns.       
Fishes are the most diverse group of vertebrates with over 30,000 species, and display a stunning range of phenotypic and behavioral characteristics enabling them to use a great variety of aquatic habitats. The genetic makeup of a fish largely determines the resources it can use, such as specialized pharyngeal jaws to crush molluscs or physiological optimization to specific thermal regimes. Most often these specializations are the result of fortuitous changes in the genetic material over short and long periods of evolutionary time. Genetic rearrangement resulting from hybridization and introgression has the potential to create novel characteristics that may affect diversification.
    In pursuit of my interest I combine several lines of research involving considerable field and lab work, including; phylogenetics, population genetics, natural history, community composition through time, and determination of pre- and post-zygotic isolating mechanisms.
I currently use Next Generations Sequencing methods in combination with traditional sequencing methods to document patterns and chronology of gene flow and isolation among populations and species. Information on natural history, community composition, and tolerance data for species comes from literature when available, but I have recently relied more on biotic data from government agencies and experimental determination.

Benjamin P. Keck
Lecturer, Biological Sciences
Curator, David A. Etnier Ichthyological Collection
University of Tennessee
Knoxville, TN  37996