— AFTER a tantalisingly successful run at sequencing parts of the extinct woolly mammoth's genome, the project is now stalled for lack of funds.
Hendrik Poinar of the McMaster Ancient DNA Centre at McMaster University in Hamilton, Ontario, and his team hope that sequencing the genomes of extinct animals will reveal otherwise inaccessible data on their evolutionary history, population, diversity and other key traits. Cracking the woolly mammoth genome might help solve the mystery of what killed off these animals as the last ice age waned about 12,000 years ago, and provide hints about the demise of their fellow megafauna.
Until recently, only mitochondrial DNA from fossilised remains of mammoths had been sequenced. Nuclear DNA was a much more difficult proposition because the sequence is far longer and there are only two strands per cell. Until this year, only a few nuclear genes had been sequenced from frozen mammoths.
Then in January, Poinar, along with Ross MacPhee of the American Museum of Natural History in New York City and colleagues, announced that they had run a gram of mammoth bone through a new machine that sequenced 28 million base pairs from small fragments of DNA. They used computer analysis to match 13 million of those base pairs to the published genome of the African elephant. The overlap between mammoth and elephant was 98.55 per cent, which is consistent with an evolutionary split between the two about 5 million years ago (Science, vol 311, p 392).
Last month, Poinar told delegates at a meeting of the Society of Vertebrate Paleontology in Ottawa that his team's results had improved over seven additional runs, with each run yielding 20 million base pairs, adding up to a few per cent of the mammoth genome. The team now needs about $500,000 to pay for 100 more runs on the sequencing machine and is applying for grants, MacPhee says. "We accept cheques in any convertible denomination."
The mammoth is a logical starting point for studying extinct giant animals from the ice age. Its remains are among the most abundant in permafrost, and the fact that its genome is similar to that of the modern elephant is a boon. Comparing the two genomes allows scientists to weed out sequences that belong to contaminants in the fossil remains, such as soil bacteria.
Efforts to sequence other extinct species could follow success with the woolly mammoth. French explorer Bernard Buigues has collected and stored remains from more than 1000 frozen ice-age fossils - including those of musk oxen, moose and caribou - in a cave he dug out of the Siberian permafrost, and is cooperating with Poinar's team. The same technique is also being used to sequence the Neanderthal genome (see "The Neander code")