A team of Swedish scientists has successfully extracted and reconstructed the world's oldest DNA from the tooth of a Siberian mammoth, which roamed Earth over a million years ago. Also known as deoxyribonucleic acid, the all-important molecule — which contains the genetic instructions for the development and function of living things. — provides new insights into the evolution of the ancient Ice Age giants. Prior to this, the oldest DNA sequenced came from the bone of a horse that trotted around Canada about 700,000 years ago.