James H. Marden

Functional genomics, Biomechanics, Physiology, Ecology, Evoltuion, and Behavior of Flying Insects

In the most general terms, I am interested in how animals work, and why they work that way. I investigate both mechanistic details of animal physiology, along with ecological and historical reasons why particular physiological mechanisms have evolved. I work primarily with insects because they are readily available, fantastically diverse, and ecologically/economically important.

Projects presently underway in my laboratory primarily involve characterizing the transcriptome (all gene-coding regions) of species that have ecological importance in order to develop genomic infrastructure to support mechanistic studies. Using that approach, we are presently examining the functional genomics of dispersal and female fecundity in a butterfly (Melitaea cinxia) that is a model system for metapopulation biology.

We have a long-running interest in the way alternative splicing of a muscle gene, troponin-t, affects contractile performance. We have discovered recently that quantitative variation in the relative abundance of troponin-t splice forms is tightly related to the body weight of both insects and mammals. This provides a molecular indicator for how much a body “thinks” that it weighs. My lab is collaborating with colleagues at Hershey College of Medicine to examine physiological conditions that disrupt normal troponin-t splicing, including the effects of obesity.

I have a long-standing interest in the way size and allometry (scaling) affect animal performance and energetics. We recently have shown that the scaling of force output by biological motors extends to human-designed motors as well. Exploring the basis for such relationships is an ongoing interest.

Wheat, C. W., C. Haag, J. H. Marden, I. Hanski, and M. Frilander. 2010. Evidence for balancing selection at a candidate gene (Pgi) influencing ecological dynamics in a butterfly metapopulation. Mol Biol Evol. 27: 267-81.

Niitepõld, K., A. D. Smith, J. L. Osborne, D. R. Reynolds, N. L. Carreck, A. P. Martin, J. H. Marden, O. Ovaskainen, and I. Hanski. 2009. Flight metabolic rate and Pgi genotype influence butterfly dispersal rate in the field. Ecology 90: 2223-2232.

Marden, J. H., H. W. Fescemyer, M. Saastamoinen, S. P. MacFarland, J. C. Vera, M. J. Frilander, and I. Hanski. 2008. Weight and nutrition affect pre-mRNA splicing of a muscle gene associated with performance, energetics and life history. Journal of Experimental Biology 211: 3653-3660.

Vera, J. C., C. W. Wheat, H. W. Fescemyer, M. J. Frilander, D. L. Crawford, I. Hanski, and J. H. Marden. 2008. Rapid transcriptome characterization for a non-model organism using 454 pyrosequencing. Molecular Ecology 17: 1636-1647.

Marden, J. H. 2008. Evolution and physiology of flight in aquatic insects. In: Aquatic Insects: Challenges to Populations Ed. J. Lancaster. CABI Press.

Marden, J. H. 2008. Dragonfly flight performance: a model system for biomechanics, physiological genetics, and animal competitive behavior. In: Dragonflies: Model Organisms for Ecological and Evolutionary Research Ed. A. Córdoba-Aguilar. Oxford University Press.

Marden, J. H. 2008. Quantitative and evolutionary biology of alternative splicing: how changing the mix of alternative transcripts affects phenotypic plasticity and reaction norms. Heredity 100: 111-120.

Bejan, A. and J. H. Marden. 2006. Unifying constructal theory for scale effects in running, swimming, and flying. Journal of Experimental Biology 209: 238-248.

Haag, C. R., M. Saastamoinen, J. H. Marden, and I. Hanski. 2005. A candidate locus for variation in dispersal rate in a butterfly metapopulation. Proceedings of the Royal Society of London B 272: 2449-2456.