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Genetic Studies Confirm A Mathematical Model For The Mechanism That Generates Our Fingers And Toes

Dr. and her research team at the contributed to a multidisciplinary research project that identified the mechanism responsible for generating our fingers and toes, and revealed the importance of gene regulation in the transition of fins to limbs during evolution. Their scientific breakthrough is published in the prestigious scientific journal Science.

By combining genetic studies with mathematical modeling, the scientists provided experimental evidence supporting a theoretical model for known as the Turing mechanism. In 1952, mathematician proposed mathematical equations for , which describes how two uniformly-distributed substances, an activator and a repressor, trigger the formation of complex shapes and structures from initially-equivalent cells.

“The Turing model for pattern formation has long remained under debate, mostly due to the lack of experimental data supporting it,” explains Dr. Rushikesh Sheth, postdoctoral fellow in Dr. Kmita’s laboratory and co-first author of the study. “By studying the role of during limb development, we were able to show, for the first time, that the patterning process that generates our fingers and toes relies on a Turing-like mechanism.”

In humans, as in other mammals, the embryo’s development is controlled, in part, by “architect” genes known as Hox genes. These genes are essential to the proper positioning of the body’s architecture, and define the nature and function of cells that form organs and skeletal elements.

“Our genetic study suggested that Hox genes act as modulators of a Turing-like mechanism, which was further supported by mathematical tests performed by our collaborators, Dr. and his team,” adds Dr. Marie Kmita, Director of the Genetics and Development research unit at the IRCM. “Moreover, we showed that drastically reducing the dose of Hox genes in mice transforms fingers into structures reminiscent of the extremities of fish fins. These findings further support the key role of Hox genes in the transition of fins to limbs during evolution, one of the most important anatomical innovations associated with the transition from aquatic to terrestrial life.”


The study published in Science was a collaborative project between the teams supervised by Drs. Marie Kmita (IRCM), James Sharpe (CRG Barcelona, Spain) and Maria A. Ros (University of Cantabria, Spain). The research conducted at the IRCM was funded by the Canadian Institutes of Health Research and the Canada Research Chairs Program. The article’s second first author Is Luciano Marcon from the European Molecular Biology Laboratory (EMBL) and the Pompeu Fabra University in Spain.

For more information on this scientific breakthrough, please refer to the article summary published online by Science: http://www.sciencemag.org/content/338/6113/1476.

Marie Kmita obtained a PhD in cell and molecular biology from the Université de Reims in France. She is an Associate IRCM Research Professor and Director of the Genetics and Development research unit. Dr. Kmita is also Assistant Professor-Researcher in the Department of Medicine (accreditation in molecular biology) at the Université de Montréal, and Adjunct Professor in the Department of Medicine (Division of Experimental Medicine) and the Department of Biology at McGill University. Dr. Kmita holds the Canada Research Chair in Molecular Embryology and Genetics.

Institut de recherches cliniques de Montreal