An international team of researchers has sequenced hemoglobin genes from the DNA of three permafrost preserved wooly mammoths that lived between 25,000 and 43,000 years ago. Scientists were able to convert a plasmid containing the genetic information from Asian elephant hemoglobin into one identical to that of a woolly mammoth. The plasmids were then inserted into modern-day E. coli bacteria, which faithfully manufactured the mammoth protein. (Credit: Wikimedia Commons)

CARNEGIE-MELLON (US)—Hemoglobin from an authentic woolly mammoth has been given new life by an international team of researchers.

“We’ve managed to analyze living attributes of an animal that hasn’t existed for thousands of years,” says team leader Kevin Campbell of the University of Manitoba. “This is quite amazing, given that biochemical features do not fossilize.”

“It has been remarkable to bring a complex protein from an extinct species back to life and discover important changes not found in any living species,” adds collaborator Alan Cooper, director of the Australian Centre for Ancient DNA at the University of Adelaide. “This is true paleobiology.”

The team sequenced hemoglobin genes from the DNA of three permafrost-preserved Siberian mammoths that lived between 25,000 and 43,000 years ago. Details were published April 2 in the journal Nature Genetics.

The genetic codes were sent to Chien Ho, professor of biological sciences at Carnegie Mellon University.

Using recombinant DNA methods, Ho and his colleague, Tong-Jian Shen, were able to convert a plasmid containing the genetic information from Asian elephant hemoglobin into one identical to that of a woolly mammoth.

The plasmids were inserted into modern-day E. coli bacteria, which then faithfully manufactured the mammoth protein. “This is a very powerful way to study evolution,” Ho says.

“The resulting hemoglobin molecules are no different than ‘going back in time’ and taking a blood sample from a real mammoth,” explains Campbell.

“This is the first time we’ve been able to study biological processes of an extinct animal in precisely the same way we would for living species.”

Team member Roy Weber at the University of Aarhus, Denmark, tested the “revived” mammoth proteins and confirmed that three highly unusual changes in the hemoglobin sequence allowed mammoth blood to deliver oxygen to cells even at very low temperatures, something living elephant blood is unable to do.

This indicates that mammoths, which initially evolved in tropical Africa, developed a natural adaptation to the harsh Arctic environment that allowed them to cool down their extremities and minimize costly heat loss.

“This is one piece of the puzzle as to how these animals moved into and survived the extreme conditions of the Arctic,” says Campbell.

“Our approach opens the way to understand how, at the molecular level, extinct species adapted to paleoenvironments that are no longer present on Earth.”

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