> The researchers recovered ancient DNA of Neanderthals by extracting the DNA from the femur bones of three 38,000-year-old female Neanderthal specimens from Vindija Cave, Croatia, and other bones found in Spain, Russia, and Germany.[8] Only about half a gram of the bone samples (or 21 samples each 50–100 mg[1]) was required for the sequencing, but the project faced many difficulties, including the contamination of the samples by the bacteria that had colonized the Neanderthal's body and humans who handled the bones at the excavation site and at the laboratory.
https://en.wikipedia.org/wiki/Neanderthal_genome_project
2^(38000/521)=10^22, so there must be other effects. That Nature article says
> The team predicts that even in a bone at an ideal preservation temperature of −5 ºC, effectively every bond would be destroyed after a maximum of 6.8 million years. The DNA would cease to be readable much earlier — perhaps after roughly 1.5 million years, when the remaining strands would be too short to give meaningful information.
which I don't know how to square with the 521 year figure. I think maybe 521 years is at the high temp?
I think you're right that it's a temperature thing.
