Friday, February 25, 2011

How the leopard REALLY got his spots: Scientists identify gene that determines patterns of colour on mice

By FIONA MACRAE

Distinctive: Scientists have unlocked a gene that determines patterns of colour on the coats of mice - and believe it plays a role in the formation of leopard markings


Kipling would have us believe that the leopard got its spots to hide in the ‘stripy, speckly, patchy-blatchy shadows’ of the African forest.

But the reality behind the big cat’s distinctive coat is much more prosaic.

Scientists have identified a gene that determines the patterns of colour on the coats of mice.

While the research is still preliminary, they believe that the stretch of DNA may also play a role in the formation of the markings of other animals – including the leopard’s spots.

Researchers already knew that the gene, called Agouti, affects how deeply adult fur is shaded.

But the latest research also implicates it in the formation of patterns.

The finding, from a team at Harvard University in the US, comes from a study of deer mice, which like many creatures, has a lighter-coloured belly than back.

The researchers showed that small changes in how active the Agouti gene is in the womb affects the distribution of pigment on the animal’s body in later life.


Study: The scientists found the Agouti gene when they examined the difference in colour between the belly and back of deer mice


In the case of the deer mice, the gene is highly active in the unborn rodent’s belly, where it delays the maturation of the cells that will eventually produce pigments.

‘This leads to a lighter-coloured belly in adults, which is the most common colour pattern across a wide variety of vertebrates, from fish to antelope,’ said researcher Hopi Hoekstra.

The study’s lead author, Marie Manceau, said: ‘The question of how colour patterns are established in vertebrates has been a black box.

‘Taking advantage of the simple colour pattern of deer mice we showed that small changes in the activity of a single pigmentation gene in embryos generate big differences in adult colour pattern.’


Next up: The scientists who conducted the research now hope to study other animals, including how zebras got their stripes


The researchers, who detailed their findings in the journal Science now plan to dissect the mechanics of more complex colour patterns, starting with striped mice and squirrels the ‘racing stripes’ of chipmunks.

The leopard’s spots and the zebra’s stripes are also within their sights.

They said: ‘It is hard not to speculate that Agouti plays a role in generating more complex patterns, from stripes to spots, in a diversity of vertebrates.’


source: dailymail


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