Ten woolly mammoths that died up to 50,000 years ago have had their DNA sequenced using a technique that could revolutionise genetic testing of extinct creatures.

DNA sequences from mammoth remains were so detailed that they are expected to cast light on why the animals became extinct. Using a new technique for extracting DNA, researchers were able to carry out the analysis with strands of hair instead of fragments of bone.

The woolly mammoth hair had been so well preserved that it provided the most accurate DNA sequencing of the extinct animals yet achieved. One of the animals used in the study dated back 50,000 years and its hairs allowed scientists to obtain the oldest complete sequence of mitochondrial DNA.

Three mammoths had been subjected previously to DNA sequencing, two with bone fragments and the third with a sample of muscle tissue.

Results from hair assessed using the sequencing-by-synthesis (SBS) technique were more detailed than bone and muscle samples. Importantly, said researchers, the SBS extraction technique required smaller quantities of ancient material and caused less damage to the preserved specimens.

Mammoths roamed the landscape for about six million years and their disappearance about 10,000 years ago – with a handful of dwarf mammoths surviving on remote Siberian islands until little more than 2,000 years ago – has remained a mystery.

Scientists involved in the study now hope to gain insights into their extinction. Initial and unpublished analysis suggests the creatures had little genetic diversity, which might have contributed to their downfall.

Tom Gilbert, of the University of Copenhagen, the lead author of the DNA sequencing study, published in the journal Science yesterday, said that by sampling more mammoth remains it should be possible to estimate ancient population levels and lifestyles. “We can do things like looking at how closely related to other animals they were, their population structure and how big the populations were.

“One of the most interesting things we’ve found is [the mammoths sampled] span 40,000 years and they are all extremely similar. It’s not a hugely diverse population.”

To the astonishment of the research team, the SBS technique succeeded in providing a sequence even for a sample that had been stored at room temperature for 200 years. The sample was that of the first mammoth recorded, the 36,000-year-old Adams Mammoth, which was found in 1799 and dug up from 1804-06.

The sequencing technique allowed scientists to obtain detailed results from as little as 0.2 grams of material, about 20 strands of hair, and the technology is advancing so rapidly that researchers believe they will soon be able to achieve the same results from a single hair.

Hairs without roots were thought to offer little chance of accurate sequencing but the study found that it is a rich source of mitochrondrial DNA. Researchers suggested the genetic material was protected by keratin.

Samples yielded between 5 and 26 times as much mitochondrial than had previously been extracted from mammoths. Furthermore, the proportion of the sequence damaged or contaminated was 0.24-0.9 per cent compared to 1.7 per cent for bone.

Stephan Schuster, of Penn State University, said that they would now investigate more extinct creatures. “We plan to use hair and other keratin-containing body parts, such as nail and horn, to untangle the secrets of populations that lived long ago,” he said.

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