It Seems That A Leopard CAN Change Its Spots
Do you remember that wonderful Rudyard Kipling story, How The Leopard Got His Spots. Kipling described how the leopard’s Ethiopian friend imprinted marks on the leopard’s fur with his black fingers making repeated patterns of five spots, so the leopard would be camouflaged. This fanciful and literary explanation is obviously not true, but up to now scientists haven’t been able to come up with any better theory as to how animals develop their distinctive spots, stripes or markings. But science now thinks it has the answer, at least according to a paper published in Nature (April 7) by researchers from Howard Hughes Medical Institute at the University of Wisconsin-Madison, US.
What the Wisconsin-Madison researchers have found is a protein that ‘tells’ other cells what colour they should be. This protein, acting as colour-consultant for the body, is called a morphogen. The scientists carried out their experimentation on the simple fruit fly, Drosophila guttifera, an insect that has sixteen different patterns on its wings. As the wing develops, the morphogen rushes through the body to where it is needed and triggers specific cells to make a pigment.
The research took three years and the sacrifice of thousands of fly embryos. After the scientists had identifed the protein morphogen and its encoding gene called Wingless, they were able to inject this gene into the fruit fly embryos and manipulate the wing markings. As a result, they were able to trigger the development of stripes instead of the usual spots. The same theory and practice can be applied to any animal.
Is this the dawn of GM-Pets with their designer markings? Will we be able to genetically-engineer cats with the spots of a butterfly, or put zebra-stripes on our pet mice? Science tells us it is possible, but only ethics can tell us whether it should be done.
Scientists may be able to change the leopard’s spots, but only Kipling can so beautifully describe them:
Now you are a beauty!’ said the Ethiopian. ‘You can lie out on the bare ground and look like a heap of pebbles. You can lie out on the naked rocks and look like a piece of pudding-stone. You can lie out on a leafy branch and look like sunshine sifting through the leaves; and you can lie right across the centre of a path and look like nothing in particular. Think of that and purr!