Woolly mammoth's cold adaptation

Changes in the genes encoding woolly mammoth hemoglobin may have been involved in its adaptation to cold environments of the Arctic, according to a new report published online this week in Nature Genetics.

Ancestors of woolly mammoths and modern-day elephants originated in equatorial Africa, though members of the mammoth lineage migrated to higher latitudes 1.2-2.0 million years ago. This migration coincided with climate changes and a drastic cooling in high-latitude Arctic environments.

Hemoglobin, a protein important in red blood cells, binds and carries oxygen, although its ability to release oxygen to tissues is inhibited at low temperatures. To investigate whether changes within hemoglobin might be linked to the mammoth's adaptation to cold environments, Kevin Campbell, Alan Cooper and colleagues sequenced the genes encoding hemoglobin from a 43,000 year-old woolly mammoth and compared it to modern-day African and Asian elephants. The scientists found changes in mammoth hemoglobin that facilitate release of oxygen at cold temperatures.