Cambridge, Mass. - August 10, 2011 - Between conception and birth, the human gut grows more than two meters long, looping and coiling within the tiny abdomen. Within a given species, the developing vertebrate gut always loops into the same formationhowever, until now, it has not been clear why.
Using a combination of experimental observations, biological and biophysical manipulations, theory, and computation, researchers at Harvard have shown that a "simple" balance of forces determines the form of the gut.
The finding may shed light on how the gut has been able to evolve to accommodate changes in diet.
The interdisciplinary research, published in the August 4th issue of Nature, demonstrates that differences in growth rates between the gut tube and the neighboring mesenteric tissue force the tube to coil, regardless of the space constraints.
"One might think that the gut tube coils because it is restricted by the size of the abdominal cavity. That's actually not the case," says co- author Thierry Savin, a postdoctoral research associate at Harvard's School of Engineering and Applied Sciences (SEAS). "The gut coils because when the mesentery and the gut tube grow at different rates while remaining attached, coiling is the only possible result."
"A simple mathematical scaling theory combined with computations showed that these patterns are quantitatively predictable using experimentally derived measurements with no adjustable parameters. This allows for a study of the pattern as a function of developmental timeand even across species," explains co-author L. Mahadevan, Professor of Applied Mathematics at SEAS, Professor of Organismal and Evolutionary Biology and Physics, and member of the Wyss Institute for Biologically Inspired Engineering and the Kavli Institute for Bionano Science and Technology at Harvard.
In a developing vertebrate embryo, the gut tube is connected along its length to an elastic she
|Contact: Caroline Perry|