But mammoths rarely die in the controlled-temperature conditions necessary to preserve eggs without harm. Intact organs are seldom found. To retrieve viable sperm or eggs “seems an even more remote chance,” said Alex Greenwood, a biologist at Old Dominion University in Norfolk, Va., who has worked on mammoth DNA.

Image Credit... Sergei Cherkashin/Reuters

The alternative, far more laborious, would be to analyze the sequence of DNA units in the mammoth’s genome, make a copy of the DNA, and have it take over an elephant’s egg.

Each of those steps has long seemed impossible. But advances in the last few months have made each seem slightly less daunting. Analyzing the DNA sequence is complicated by the fact that ancient DNA, when it can be retrieved at all from fossil bones, is always highly degraded. The genome in every cell breaks down after death into thousands of small fragments of DNA.

But a new kind of DNA decoding machine happens to use such fragments as its starting material. At McMaster University in Canada, Hendrik Poinar and Régis Debruyne plan to use of one the machines, from 454 Life Sciences, to reconstruct a mammoth genome. The remaining obstacle is money. If they had $1 million, they could generate a rough draft of a mammoth genome in about a month, Dr. Debruyne said.

The reconstructed sequence of DNA units would then need to be turned into an actual mammoth genome. Mammalian genomes are made up of chromosomes of about 100 million DNA units in length and are beyond the capacity of current synthesis. Still, researchers at the Venter Institute in Rockville, Md., say they are close to synthesizing the genome of a bacterium that is 500,000 units long.