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Comment by Lendal | Hacker News Reader

It's an Eocene mosquito. Dinosaurs were already extinct. Notable about this period is it was the last time there was no ice at the poles and water covered a lot more of the earth, as you can see from the map of the Eocene: https://en.wikipedia.org/wiki/Eocene which means there were probably a lot of blood-filled mosquitos around during the Eocene.

Also from the article: DNA has a half-life of ~521 years so there's no DNA left in the blood.

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And yet they keep "restoring" parts of ancient DNA from fossilized bones for further analysis. Who knows what's possible in the future, maybe they'll use frogs to fill in the blanks or something. ;)

When the bones have turned to stone there's not much to restore as the stone/minerals essentially just fill the empty shape that the body left behind. I think they can do some minor analysis still, like e.g. pigment analysis to identify possible colors. But if its just 'very old bones' you can still get DNA fragments. The chance of getting a whole strand of DNA is however pretty low. So you might be able to identify relations, but you wouldn't be able to clone them.

If you're talking about woolly mammoth DNA [0], that's around 10,000 years old.

This mosquito is around 50 million years old. The DNA in its belly is too degraded. Restoration ain't gonna happen.

[0] https://www.npr.org/2021/09/14/1036884561/dna-resurrection-j...

I just don’t know if I can truly believe that dna half life number. What dna molecule type in what condition ? What temperature? What does a long dna strand degrade into? Citations will be appreciated.

Nature

https://www.nature.com/articles/nature.2012.11555

Scientific American

https://www.scientificamerican.com/article/dinos-dna-demise-...

The Royal Society

https://royalsocietypublishing.org/doi/10.1098/rspb.2012.174...

Scitech Daily

https://scitechdaily.com/researchers-calculate-that-dna-has-...

Thanks. Looks like the royal society link is the original work, but the nature editorial also mentions the same - it’s still possible we might have higher stability in other conditions (they only loooked at dna in bone samples). Not saying we will hold hope for dinosaur cloning, just that 521 years sounds too small.

DNA is stable, but still susceptible to hydrolysis. Water will eventually degrade it down to constitutive parts.

How about in amber then? How long might we expect DNA to remain intact perfectly encased in amber?

You won't find DNA that isn't in contact with a lot of water in nature, unless something actively extract the water.

The questions still seems reasonable? Maybe there exists some geological processes minerals deposits that absorbed moisture? Some kind of geothermal heating (although maybe that would just make steam permeate the surrounding area), an asteroid fragment from the Chicxulub impact that carried DNA into space??

Amber is heterogeneous in composition, but consists of several resinous bodies more or less soluble in alcohol, ether and chloroform, associated with an insoluble bituminous substance. Amber is a macromolecule by free radical polymerization of several precursors in the labdane family, e.g. communic acid, cummunol, and biformene. These labdanes are diterpenes (C20H32) and trienes, equipping the organic skeleton with three alkene groups for polymerization. As amber matures over the years, more polymerization takes place as well as isomerization reactions, crosslinking and cyclization.

Wikipedia Amber

https://en.wikipedia.org/wiki/Amber

CAN YOU REALLY PULL A "JURASSIC PARK" AND EXTRACT DNA FROM BUGS FROZEN IN AMBER?

https://www.syfy.com/syfy-wire/can-you-really-extract-dna-fr...

I love the way that map shows all the nations of our currently familiar final map all flooded and out of place... Except Ireland and Britain. Those are really the old country!

> DNA has a half-life of ~521 years so there's no DNA left in the blood.

That's true but there might be some fragments left.

It's interesting that North America is actually less covered in water on that map than it is now. No Hudson Bay, no Great Lakes. Looks like the arctic archipelago is more unified than now, but that's harder to tell.

You have billions of identical copies of the DNA molecules probably, so it might matter less if there are some breaks or errors when you sequence, if you sequence very thoroughly.. even when sequencing fresh DNA you have lots of read errors, inserts and deletes.. (haven't read the specifics of this case but I'm sure the fidelity numbers are in the articles somewhere, would be interesting!)

> Also from the article: DNA has a half-life of ~521 years so there's no DNA left in the blood.

Does this mean that the oldest creature that can be “restored” should be dead for less than 521 years old?

The article they cite says this might not apply in caves or permafrost for example. It gives ~1.5 million years as an endpoint for readability

Yeah we've sampled a full horse genome from 700,000 years ago.

It means that half the DNA is gone after 521 years. After another 521 years, half of the remaining DNA is gone too, leaving 1/4 of the original DNA.

Figure that rate of decay into your "restoration" technique to know for how long an organism can be "restored" after being dead. Does your technique require 100% of the DNA? Better catch them on asphalt. Is 50% good enough? You could probably restore Newton. You could do Paul with 6% give or take.

I don't think that analysis is right. From the original Royal Society paper:

> The average DNA half-life within this geographically constrained fossil assemblage was estimated to be 521 years for a 242 bp mtDNA sequence, corresponding to a per nucleotide fragmentation rate (k) of 5.50 × 10–6 per year.

If there is a 50% chance that a 242 base pair sequence has a break in 500 years, you will be able to recover the full sequence in way more than 50% of 500 year old samples. First, you have many copies of the same DNA fragment in a macroscopic drop of blood, so some will not have a break. Second, even if it's older and all strands have at least one break, you can look at a bunch of half strands or tenth strands and infer the complete sequence. Likewise, if I had a thousand copies of a book where each copy had a few destroyed pages, it would not be hard to reconstitute the entire contents of the books.

I think the above rate of decay would allow for recovery of the sequence in a sample after probably tens of thousands of years. This is why mammoths, but not dinosaurs, are typically the targets for brining back extinct mammals.

Interesting perspective, thank you. I'd like to see the comments of somebody versed in the field.

You, sir, ruined my dreams in an instant.

Damn I want dinosaurs!

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