IT is as defining a Scottish characteristic as a love of whisky , an appreciation for golf and an urge to wear a kilt no matter what the formal occasion. And now scientists say that the secret of the flowing red locks sported by many a son and daughter of Caledonia can be found in their genes. Researchers at the University of Edinburgh studying how hair gets its distinctive colour say they have solved the mystery of the way redheads inherit their flaming hue - and it is more complicated than first believed. For several years it has been thought that red hair is controlled by a single gene, called MC1R, which caused follicles to start sprouting ginger strands when 'switched on. But fresh experiments have found that instead of just one gene, eight have to come into play and interact before red hair appears.