May 3, 2010

Mammoths Kept Warm With Antifreeze Blood

Scientists discovered that mammoths had blood that displayed "antifreeze" like qualities, which kept their bodies supplied with oxygen at sub-zero temperatures.

The journal Nature Genetics reported that scientists extracted a blood protein, known as hemoglobin, from mammoth remains. The study of the hemoglobin led researchers to find those antifreeze properties.

The hemoglobin protein is found in red blood cells where it binds to and carries oxygen. The scientists found that mammoths possessed a genetic adaptation that allowed the protein to release oxygen into the body even at low temperatures. The ability of hemoglobin to release oxygen to the body is usually inhibited in cold temperatures.

The mammoth DNA protein was taken and sequenced from three Siberian mammoths, many thousands of years old, which were preserved in permafrost. The mammoth DNA sequences were converted into RNA and then injected into E. coli bacteria. The bacteria faithfully produced the mammoth protein.

"The resulting hemoglobin molecules are no different than 'going back in time' and taking a blood sample from a real mammoth," co-author Kevin Campbell, from the University of Manitoba in Canada, told BBC News.

The "revived" mammoth proteins were found to contain three unique changes in the hemoglobin sequence which allowed mammoth blood to deliver oxygen to cells even in very cold temperatures.

"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," co-author Alan Cooper, director of the Australian Center for Ancient DNA at the University of Adelaide, told BBC News.

Without the genetic adaptation of the protein, mammoths would have had to eat much more to replace the needed energy they lost during the winter.

Although the ancestors of modern elephants and woolly mammoths lived in Africa, members of the mammoth lineage migrated to higher latitudes between 1 and 2 million years ago.

Scientists said that this genetic adaptation may have been crucial in allowing ancestors of the mammoth to thrive in the colder environments during the Pleistocene era.


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