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Ever wondered how a zebra gets its stripes, or how, from a few cells, a plant or animal grows into its particular shape? As an organism grows, different sets of genes are expressed in different parts, which affects development. But how? What controls shape as an organism develops? How does the changing shape and size of an organism as it grows affect spatial and temporal patterns of gene expression?

This is an exciting time for developmental biology, as recent advances in molecular biology, 2D and 3D imaging, and computer technology now make it possible to investigate these questions.

In our lab, we use a combination of experimental work (e.g. fluorescence microscopy), computational tools (e.g. image processing) and computational modeling to investigate mechanisms of morphogenesis.

We are more particularly interested in the coordination of tissue growth and branching/network patterning, and are using plant leaves and fish fins as our two main model systems. Long term, potential applications include 1) horticulture and crop amelioration, as leaf size and plant vasculature are closely correlated to plant morphology and biomass, 2) regenerative medicine, as Danio rerio (the zebrafish) is emerging as a model system to study fundamental mechanisms of bone growth and regeneration.

Below are sample projects.

Quantifying leaf growth patterns

We developed a methodology for describing growth patterns at the three-dimensional surface of leaves (Remmler and Rolland-Lagan, 2012), based on the tracking of fluorescent microparticles applied to the leaf surface in multiple samples tracked over multiple time points.




In vivo analysis of vein pattern formation

By tracking and quantifying vein formation in vivo in transgenic Arabidopsis thaliana plants with fluorescent markers of leaf vasculature, we can study the relation between growth and vein patterning processes.




Morphogen-based models of fin ray patterning

Fins of teleost fish can regenerate following partial amputation. We proposed a morphogen-based simulation model which seems to account for the control of bone growth and joint spacing during caudal fin development and regeneration (Rolland-Lagan et al., 2012). In particular, the model accounts for how an amputated fin regains its shape. We have also been testing the model through the quantitative analysis of fin ray patterns during growth and regeneration (see next project).




Quantitative spatial descriptions of fin ray patterns

We developed software for the quantitative analysis of fin ray patterns. As an example of the kind of data that we can obtain, the picture on the left shows a 'likely fin', as computed from fifteen images of fins at the same developmental stage (the three different images represent three kind of data extracted from the quantified patterns). Using the software, can quantify bone growth and ray patterning during development and regeneration, and the data obtained can be used to test and refine simulation models of fin development (see previous project).




Basis of fin morphological variation

Now that we have the basis of a model for the control of fin ray patterning, we are testing how varying model parameters can generate fins with different shapes and bone joint patterns. In particular, the model can make predictions regarding joint patterns in fins of different shapes. We have been combining experimental and simulation studies to investigate the basis of fin morphological variation, within and between fish species.