The first hurdle was simply finding enough Neanderthal DNA to sequence.

These were essentially identical to the specimens in which some American scientists had said they found ancient DNA.

In 1990, a laboratory examining evidence from the Alexandria rape found too little DNA to evaluate.

They could find mitochondrial DNA only (which means it came exclusively from either hair or nails).

The researchers found DNA from the virus in the tumors, clear proof of infection.

"It's like finding complete DNA preserved in dinosaur fossils."

They hope to use similar methods to find usable mammoth DNA.

But in addition, they found in the parasites mysterious DNA whose origin and home within the cell remained unknown.

Also, a few scientists have been able to find intact mitochondrial DNA in some samples.

"What do you want to bet we find different DNA on the butts?"