Animal stripes have perplexed researchers for years. Studies have been carried out since the 1950s in an effort to understand how they develop and Sean Megason and Tom Hiscock from the Harvard Medical School have taken their own steps to unravel the mysteries of animal stripes.
In a study published in the journal Cell Systems, Megason and Hiscock detail the results of their work, which they said was driven by the desire to come up with a simple yet comprehensive model that includes all of the different explanations so far produced regarding animal stripes. With their model in place, Hiscock said that it is now possible to determine what is common among mechanical, cellular and molecular hyphotheses that have guided previous studies.
In truth, stripes are simple to mathematically model, with a lot of the early work on the topic done by Alan Turing. Their patterns usually come out when interacting substances produce low and high concentrations of a certain type of cell, chemical or pigment. What Turing's model does not explain, however, is how stripes are oriented vertically or horizontally.
This is what the current study focused on. One surprise that Megason and Hiscock encountered is that it only requires a little change to the model to make stripes turn out vertical or horizontal. What they are unsure of, however, is how this translates to living things, like tigers.
"We can describe what happens in stripe formation using this simple mathematical equation, but I don't think we know ... exactly what molecules or cells are mapping the formation of stripes," said Hiscock.
Additionally, he said that genetic mutants that can't form their own stripes exist, but the main concern is that there is a big interaction network in place and there are any number of parameters that can affect patterns.
The master model developed during the study predicts three main deviations that have an effect on the orientation of stripes: a change in production gradient, a change in parameter gradient and physical change.
For a change in production gradient , a substance boosting the density of stripe patterns is needed, while a change in parameter gradient will require a substance that can affect one of the parameters part of the stripe-formation process. Physical change, on the other hand, entails a change involving the direction of the stripe's mechanical, cellular or molecular origin.
The study was supported by the Herchel Smith Graduate Fellowship and the National Institutes of Health.
Photo: Ross Elliott | Flickr
