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In a similar vein, scientists discovered T-Rex fossils that had bone marrow that was gellified, something that was supposed to be impossible. They could see blo

In a similar vein, scientists discovered T-Rex fossils that had bone marrow that was gellified, something that was supposed to be impossible. They could see blood cells and other structures. I've been waiting for 10+ years for followup but haven't heard anyting about it. Does anyone have any updates to that? Were they able to dig up any other information from that discover?

causality0 3y ago
You could find liquid bone marrow but I suspect the half-life of DNA itself means we'll never get anything useful out of it. It doesn't have to be dry to degrade.
- credit_guy 3y ago
  The myth of the half-life of DNA needs to die. Just one year after the article with the supposed 521 years DNA half-life was published, the DNA of a 700000 year old horse fossil was sequenced [1]. That would have been more than 1000 half-lives, so it should have been completely useless. Except that it wasn't. [1] https://www.science.org/content/article/700000-year-old-horse-becomes-oldest-creature-sequenced-genome https://www.science.org/content/article/700000-year-old-hors...
  - deleted 3y ago
    [deleted]
  - causality0 3y ago
    I can't find any scientists claiming that sequencing 700,000 year old DNA means the half-life study was incorrect, or even that it was incorrect for any other reason. Do you have sources?
    - purpleblue 3y ago
      It's math. If the half-life was 500 years, there would be nothing left to sequence after 700,000 years.
      - causality0 3y ago
        Kilograms of biological material that's been frozen for 0.7MY will contain many orders of magnitude more intact DNA than a few grams of bone marrow that's been in assorted temperatures for a hundred times as long.
        purpleblue 3y ago
        700,000 / 500 = 1400 half lives, or 2^(-1400). I'll let you do the math on how much would remain if we had 1 million tons of horse DNA with a 500 year half life. I'll even let you assume we have 1 trillion tons of horse DNA.
        causality0 3y ago
        The half-life paper itself cites a readability horizon of 1.5 million years for even non-permafrost DNA. Regardless of what the degradation rate is, reading the genome of a whole frozen animal from 0.7MY ago is much easier than reading the genome from a tiny piece of unfossilized gel that's a hundred times older. I know that feeling, my man. My shelves are covered in Jurassic Park memorabilia too. It's just not going to happen, though.
        credit_guy 3y ago
        But then what's the point of the study? DNA has a half life of 500 years except when it doesn't? If they say 500 years and then you can retrieve DNA from samples 1000 times as old, who's to say they can't go further by another factor of 100?
        causality0 3y ago
        I never said it was impossible. I meant that based on the fact DNA destabilizes over time even without an external destructive force, that is, it has a half-life, it's supremely unlikely useful genomes will ever be derived from 50+ million year old fossils.
        3y ago
  - woopsn 3y ago
    The half-life study states degradation might take "roughly 1.5 million years" in permafrost conditions. https://www.nature.com/articles/nature.2012.11555 https://www.nature.com/articles/nature.2012.11555
  - optionalsquid 3y ago
    The horse paper [1] is not a refutation of the DNA half-life paper [2]: It's worth remembering that the half-life paper dealt with samples that had "an effective burial temperature of 13.1°C", while the horse sample was obtained from the permafrost. The half-life paper even talks about DNA obtained from ice-core samples in that age-range: > The rate of depurination is influenced by temperature, among other factors, which explains why the most extreme survival of DNA was documented in approximately 450–800 kyr ice cores. And if you look at Table 1 in the half-life paper, you'll find estimated half-lifes for a range of temperatures, with an estimated half-life of 9.5k years for a 500bp DNA fragment at -5C and 47k years for a shorter 100bp fragment at the same temperature: > Still, the results indicate that under the right conditions of preservation, short fragments of DNA should be retrievable from very old bone (e.g. greater than 1 Myr). The horse paper also cites the half-life paper, but not as a refutation. [1] https://www.nature.com/articles/nature12323 https://www.nature.com/articles/nature12323 [2] https://pubmed.ncbi.nlm.nih.gov/23055061/ https://pubmed.ncbi.nlm.nih.gov/23055061/

causality0 3y ago

You could find liquid bone marrow but I suspect the half-life of DNA itself means we'll never get anything useful out of it. It doesn't have to be dry to degrade.

credit_guy 3y ago
The myth of the half-life of DNA needs to die. Just one year after the article with the supposed 521 years DNA half-life was published, the DNA of a 700000 year old horse fossil was sequenced [1]. That would have been more than 1000 half-lives, so it should have been completely useless. Except that it wasn't. [1] https://www.science.org/content/article/700000-year-old-horse-becomes-oldest-creature-sequenced-genome https://www.science.org/content/article/700000-year-old-hors...
- deleted 3y ago
  [deleted]
- causality0 3y ago
  I can't find any scientists claiming that sequencing 700,000 year old DNA means the half-life study was incorrect, or even that it was incorrect for any other reason. Do you have sources?
  - purpleblue 3y ago
    It's math. If the half-life was 500 years, there would be nothing left to sequence after 700,000 years.
    - causality0 3y ago
      Kilograms of biological material that's been frozen for 0.7MY will contain many orders of magnitude more intact DNA than a few grams of bone marrow that's been in assorted temperatures for a hundred times as long.
      - purpleblue 3y ago
        700,000 / 500 = 1400 half lives, or 2^(-1400). I'll let you do the math on how much would remain if we had 1 million tons of horse DNA with a 500 year half life. I'll even let you assume we have 1 trillion tons of horse DNA.
        causality0 3y ago
        The half-life paper itself cites a readability horizon of 1.5 million years for even non-permafrost DNA. Regardless of what the degradation rate is, reading the genome of a whole frozen animal from 0.7MY ago is much easier than reading the genome from a tiny piece of unfossilized gel that's a hundred times older. I know that feeling, my man. My shelves are covered in Jurassic Park memorabilia too. It's just not going to happen, though.
        credit_guy 3y ago
        But then what's the point of the study? DNA has a half life of 500 years except when it doesn't? If they say 500 years and then you can retrieve DNA from samples 1000 times as old, who's to say they can't go further by another factor of 100?
        causality0 3y ago
        I never said it was impossible. I meant that based on the fact DNA destabilizes over time even without an external destructive force, that is, it has a half-life, it's supremely unlikely useful genomes will ever be derived from 50+ million year old fossils.
        3y ago
- woopsn 3y ago
  The half-life study states degradation might take "roughly 1.5 million years" in permafrost conditions. https://www.nature.com/articles/nature.2012.11555 https://www.nature.com/articles/nature.2012.11555
- optionalsquid 3y ago
  The horse paper [1] is not a refutation of the DNA half-life paper [2]: It's worth remembering that the half-life paper dealt with samples that had "an effective burial temperature of 13.1°C", while the horse sample was obtained from the permafrost. The half-life paper even talks about DNA obtained from ice-core samples in that age-range: > The rate of depurination is influenced by temperature, among other factors, which explains why the most extreme survival of DNA was documented in approximately 450–800 kyr ice cores. And if you look at Table 1 in the half-life paper, you'll find estimated half-lifes for a range of temperatures, with an estimated half-life of 9.5k years for a 500bp DNA fragment at -5C and 47k years for a shorter 100bp fragment at the same temperature: > Still, the results indicate that under the right conditions of preservation, short fragments of DNA should be retrievable from very old bone (e.g. greater than 1 Myr). The horse paper also cites the half-life paper, but not as a refutation. [1] https://www.nature.com/articles/nature12323 https://www.nature.com/articles/nature12323 [2] https://pubmed.ncbi.nlm.nih.gov/23055061/ https://pubmed.ncbi.nlm.nih.gov/23055061/