Scientists use hair follicles to sequence woolly mammoth DNA

Washington, Sept 28 : Pennsylvania State University researchers have sequenced the DNA of 10 woolly mammoths that died 50,000 years ago, using a technique that could revolutionize genetic testing of extinct creatures.

In their study, ‘Whole-Genome Shotgun Sequencing of Mitochondria from Ancient Hair Shafts’, the scientists describe how the hair shafts of extinct animals can provide an ideal source of ancient DNA.

Typically, DNA sequencing from hair involves the hair root, which contains recognizable cells. In this new study appearing online in the journal Science, the researchers portray the hair shaft as DNA encased in a biological kind of plastic, protected from damage and isolated from contaminants.

The new method employed 454 Sequencing to sequence the entire mitochondria from 10 individual woolly mammoths.

Several of the hair samples investigated were up to 50,000 years old with one sample being stored in a Russian museum for 200 years at room temperature.

Scientists have previously published only seven mitochondrial genomes from extinct animals, four from ancient birds, two from mammoths, and one of the mastodon, a distant relative of mammoths.

“The challenge with sequencing ancient DNA is finding an undamaged and uncontaminated sample, and having a sequencing technology that can produce long, highly accurate sequence reads affordably,” said Stephan C. Schuster, PhD., senior author and Associate Professor of Biochemistry and Molecular Biology at PSU.

“By combining our novel method for capturing ancient DNA with 454 Sequencing, we are able to move paleogenomics from a niche application to high-throughput analysis. I can see a time of museumomics where museums will add genomic analyses to extinct species stored in collections around the world,” he said.

“This new method for preparing ancient DNA really unlocks the power of 454 Sequencing in the field of paleogenomics,” added Michael Egholm, Ph.D., vice president of research and development at 454 Life Sciences.

“While ultra-high throughput and ability to generate long, high-accuracy reads makes 454 Sequencing an obvious choice for ancient DNA sequencing, the limiting factor has always been obtaining enough high quality DNA to take advantage of the technology. The new protocol, along with 454 Sequencing, opens the door to sequence many ancient species,” Dr Egholm said. (With inputs from ANI)