Mammoth hunting with Alan Cooper
1 Jul 2010 by hdpqmpdbhq.d hdpqmpdbhq.d
Mammoths went extinct about 45,000 years ago, but a team of international scientists has succeeded in recreating the animal’s blood from DNA samples taken from bones, we find out how...
Professor Alan Cooper is part of an international team of scientists – all experts in their field – who recently succeeded in resurrecting the primary component of mammoth blood: haemoglobin. Professor Cooper is director of the Australian Centre for Ancient DNA, and was instrumental in determining mammoth haemoglobin sequences which identified evolutionary changes that allowed mammoths to minimise heat loss in harsh arctic conditions.
Why mammoths?
They’re actually a really good model organism – apart from being extinct! They moved from the tropics to the arctic relatively recently – about 2 million years ago – which involved readjusting to the sharp environmental differences between the areas. We thought that by comparing the mammoth to the Indian elephant – its closest relative – we’d be able to see these changes.
How did you actually recreate the mammoth haemoglobin?
We looked at the elephant draft genome for the ? and ? globin genes, and found the ? and ? globin had actually fused into a chimera. We figured the structure would be the same in mammoths, so created primers to target these regions and used ancient DNA methods and PCR to obtain the mammoth DNA sequences. Our colleagues in Canada used these to modify modern elephant RNA with site-directed mutagenesis to encode the mammoth sequences. The RNA was sent to Florida where it was inserted into E. coli to produce the authentic mammoth protein. This was then sent to Denmark for physiological testing to see how it would bind and release gases under different temperatures.
What were the main difficulties in doing this?
Funding was a big problem. The research took about 9 years, and in the end we didn’t find any funding source – so managed to get it all done as side projects.
We also had to avoid the many globin pseudogenes, and be careful about what genes we were actually getting. We also had to deal with damage to the DNA template and check the changes we found also occurred in other mammoth specimens.
Recreating the mammoth haemoglobin wasn’t actually that difficult – it was almost more complex to assemble the team of experts we used. Kevin Campbell, the project leader, just picked up the phone and said ‘we trying to make mammoth blood, we need your help’. All these experts in the field were keen to help.
How is this research going to be useful?
It demonstrates that we can bring back aspects of the soft biology – the physiology, the biochemistry from the past. We have good records of the hard skeleton like teeth and bone but this is a new angle for studying evolution. It gives us access to a library of protein and genome variants that evolution has cooked up and simply a huge canvas to work with. It’s the way forward for palaeobiology.
What’s next in this line of research?
We want to try the same approach on Stellars Sea Cow, which is closely related to the manatee, another of the elephant group – you wouldn’t think to look at it, but it is! They also moved from the tropics to the Bering Sea and I bet their haemoglobin has also done something funky. It’ll be interesting to see how it has solved the temperature sensitivity problem differently.
