Alan Cooper, director of the Australian Centre for Ancient DNA, poses with a mammoth bone.
Credit: University of Adelaide
"The reason the mammoth is interesting, from an evolutionary point of view, is because its relatives started in the tropics, or the temperate zone, and the mammoth moved into the cold arctic only about two million years ago," says evolutionary biologist Alan Cooper, director of the Australian Centre for Ancient DNA in South Australia, who was involved in a 2010 study that reconstructed the blood protein of a mammoth to find special adaptations to the harsh, arctic weather.
"This is the reason we chose to study it, because in 2 million years it had to rapidly adapt to cold conditions and so we figured we could see evolution in action by studying the systems that would be affected by the cold."
Cooper and his team found that mammoth haemoglobin, the substance that transports oxygen in blood, could work efficiently despite colder temperatures. "That contrasts completely with us, for example, where if you cool the blood down our haemoglobin gets sticky and doesn't want to give up oxygen, which is very bad for our tissues," he says.
The study showed that evolution had changed three key amino acids in the mammoth DNA so that the haemoglobin would remain efficient. This meant that the mammoth could lower the temperature of its extremities, like its tail, feet and ears, but keep oxygen circulating efficiently, allowing it to save a large amount of energy.
Cooper's current research investigates another species of megafauna in the same group as mammoths, Stellar's sea cow, which has evolved a similar method of dealing with extreme cold. "We think it's probably done exactly the same thing, but evolution being evolution, it's probably done it in a different way," says Cooper. "So it would be very interesting to compare the evolution of the mammoth with a cold adapted form in the same group."
For Cooper, the joy of his job as an evolutionary biologist lies in unravelling evolutionary mysteries using the study of ancient DNA. "[The best part is] these amazing animals and amazing things that have happened and using DNA to get a completely new way of looking at them," he says. "[It] enables us to answer many of these mysteries which have been around for hundreds of years and have puzzled some of the great evolutionists and scientists of the time [because] without DNA they didn't have the chance to investigate these things."
