A woolly mammoth that died 43,000 years ago is yielding the secrets of its ice age survival, as reported in the May 2, 2010 edition of Nature Genetics. Head researcher Kevin Campbell of the University of Manitoba in Winnipeg, along with his colleagues, revived the blood of an extinct mammoth in order to pinpoint the evolutionary changes in the animal's hemoglobin that allowed it to survive the frigid temperatures of the last ice age. The findings may also eventually lead to some medical advances for humans.
Mammoth Hemoglobin a Unique Adaptation
Campbell and his team used bacteria reprogrammed with the ancient mammoth DNA in order to recreate the hemoglobin that would have been present in the living animal. They were specifically searching for changes in the hemoglobin molecules that would explain how they efficiently delivered oxygen to the animal's tissues under freezing conditions.
What they found was a unique mechanism of cold resistance unlike that of other animals, such as reindeer, who currently make their home in sub-zero temperatures. This example of convergent evolution in two different species likely occurred because mammoths initially evolved from elephants in Africa and only later spread into Arctic areas.
The Mechanism of Cold Resistance
In the Nature Genetics paper, Campbell explains how the mammoth's adaptations served to keep it from freezing to death. Since extreme cold prevents hemoglobin from releasing sufficient oxygen to the tissues due to less available energy, the mammoth had to evolve a method to bypass the problem.
Consequently, the hemoglobin in the mammoth's blood evolved to lower the amount of energy needed to release oxygen, using three amino acid substitutions. Reactions in the hemoglobin molecule gave off small amounts of heat that bound to compounds in the cells and carried them away. This mechanism made the hemoglobin more energy efficient and able to withstand the conditions of the Arctic ice age.
Further Research Into Cold Adaptations
The fascinating and potentially medically useful results of this research are apparently only the beginning. Campbell and his team would also like to study the hemoglobin molecules of other extinct and cold-adapted creatures like the woolly rhinoceros and the Steller's sea cow. Campbell also points out that the research could lead to further study of the use of cold to treat heart attacks and other ailments in humans.
Sources:
Campbell, Kevin L. et al. "Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance". Nature Genetics. May 3, 2010 .
O'Hanlon, Larry. "Mammoth blood revived by bacteria". MSNBC. May 3, 2010 .
Jenny Ashford - Jenny Ashford is a writer and graphic artist from central Florida. Her main area of interest in her Suite 101 articles is science, with a ...
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