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DNA obviously does not behave like radioactive isotopes, so the half-life is dependent on a lot of external factors. The study presents a model for estimating t

DNA obviously does not behave like radioactive isotopes, so the half-life is dependent on a lot of external factors. The study presents a model for estimating the half-life of DNA for a given storage temperature assuming otherwise similar conditions to their reference samples. That's obviously useful for anyone working with ancient DNA, since it helps guide attention to samples that could potentially contain recoverable DNA. The 521 years is just the half-life they estimated for their samples. Those are the empirical results, so it makes sense to highlight those in the title, as opposed to estimates from their model. I don't mean to be rude, but please read the fine manuscript. It's open access, so you don't need to pay

credit_guy 3y ago
If you have a bunch of observations, you can fit an exponential through them. You can do that in Excel. Here, let me just quickly do that for the half life of the buildings in Europe. ... Ok, done, it's 63 years. Should I publish an article? What conclusions does one draw? The usefulness of a model is how well it can extrapolate. 63 years means I should not find any buildings that are 2000 years old, and still the Pantheon is standing there just fine. Then what exactly is the claim? That it's possible to fit an exponential, but the exponential can't be used for inferring anything outside of my training sample? And, no you are not being rude. But since you seem to have read the article, can you give me a few pointers why you think it's a good investment of someone else's time to go ahead and read it too? And don't be shy to use Machine Learning or Statistics jargon, we are on Hacker News here, everyone understands concepts like in-sample, out-of-sample, goodness of fit, overfitting and such.
- causality0 3y ago
  You disagree with the 521 paper, but I'm not sure what your position is. Are you positing that DNA will not destabilize on its own unless subject to a particularly hostile environment? Are you saying it has a half-life but it's so much larger than 500 years that you expect usable DNA to be found in unfossilized dinosaur bone marrow?

credit_guy 3y ago

If you have a bunch of observations, you can fit an exponential through them. You can do that in Excel. Here, let me just quickly do that for the half life of the buildings in Europe. ... Ok, done, it's 63 years. Should I publish an article? What conclusions does one draw? The usefulness of a model is how well it can extrapolate. 63 years means I should not find any buildings that are 2000 years old, and still the Pantheon is standing there just fine. Then what exactly is the claim? That it's possible to fit an exponential, but the exponential can't be used for inferring anything outside of my training sample? And, no you are not being rude. But since you seem to have read the article, can you give me a few pointers why you think it's a good investment of someone else's time to go ahead and read it too? And don't be shy to use Machine Learning or Statistics jargon, we are on Hacker News here, everyone understands concepts like in-sample, out-of-sample, goodness of fit, overfitting and such.

causality0 3y ago
You disagree with the 521 paper, but I'm not sure what your position is. Are you positing that DNA will not destabilize on its own unless subject to a particularly hostile environment? Are you saying it has a half-life but it's so much larger than 500 years that you expect usable DNA to be found in unfossilized dinosaur bone marrow?