"When you take back to the lab, you realize that they're pretty heavily degraded," Poinar told LiveScience.
For cloning, intact DNA is needed, as the process requires replacing the DNA in an elephant egg with a mammoth's genome, then gestating the egg inside an elephant.
But time and harsh weather conditions inexorably degrade DNA, splitting it up into millions of tiny snippets that are extremely difficult to piece together. For instance, a 2012 study found that in bone, half of the chemical bonds in DNA break down within 521 years after death, and the genetic material degrades completely by 6.8 million years.
Elephant in Disguise?
If the white blood cells -- or more likely, tissues -- from the recently discovered mammoth are in fairly good condition, then there may be longer intact DNA snippets, which should be easier to piece together, Poinar said.
Either way, the mammoth genome would probably be reconstructed by using the elephant genome as the blueprint.
By comparing genomes, researchers would try to identify the key genes that create distinctive traits, such as body size, the tusks and shaggy coats of the extinct creatures, and tack those in to the elephant genome, Poinar said.