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Possible dinosaur DNA has been found

scientificamerican.com

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Re: Possible dinosaur DNA has been found

#111

Post by andbberger »

londons_explore wrote: post #67
credit_guy wrote: post #46

Earlier quoted context omitted.

> DNA has a half life of ~500 years DNA is not a radioactive material. It decays, but there's no absolute law like the radioactive decay, where the half life is the same for every microgram of the same substance everywhere in the world. The average half-life may be 500 years, but there can be situations where the DNA is exceptionally well preserved due to local circumstances. As a simple analogy: the average half lif…

I believe the laws of thermodynamics do set bounds on the breakdown rate of molecules at a specific temperature... No molecule is 100% stable... Every molecular bond will break eventually due to random thermal noise...

Thermodynamics do not set any such bounds, but equilibrium statistical mechanics does describe temperature-dependent state transitions.

Re: Possible dinosaur DNA has been found

#112

Post by DavidSJ »

andbberger wrote: post #109
colinnordin wrote: post #101

Assuming we had millions of 3D-scans of different kinds of animals and their full DNA sequence. Wouldn't it be interesting to try to use generative ML methods to generate a dinosaur DNA based on a 3D model?

I suppose everything looks like a nail when you've got a few GPUs. Besides, the sequence alone is not the full state. You have to also consider expression and regulation and all that; epigenetics.

I wonder:

Could you normally have two viable lineages, each with the same DNA, and each with a different expression of that DNA which is stably conserved over many generations, purely due to womb environment, etc.? In other words, if you cloned a woolly mammoth using an elephant surrogate, might the great great great great grandchildren of this clone still have some characteristics that are due to having an elephant surrogate ancestor?

Or would there be a tendency to converge to a single stable expression due entirely to genetics?

It‘s obvious that in principle the answer could go either way, but I’m not sure whether that’s true in practice, with naturally occurring organisms and naturally occurring DNA sequences. For the sake of this question, one is also tempted to exclude post-natal “cultural” transmission, but it’s not clear that can be easily distinguished.

Re: Possible dinosaur DNA has been found

#113

Post by EmilioMartinez »

Robotbeat wrote: post #59
burtonator wrote: post #49

Earlier quoted context omitted.

There was a paper not long ago saying that the DNA half life is about 500k years or so and that most of the DNA would be degraded. The issue I had with this is why can't we reassemble chunks of DNA like we can with a puzzle. I'm certain specialized algorithms exist within DNA analysis for this reason. This isn't my field and there are already algorithms that exist on the top of my head that could solve this issue. Th…

What does half life of 500,000 years mean? Does that mean any given gene will, on average, split every 500,000 years? Or become unusable in 500,000 years? 65 million years would mean 130 halvings. Basically nothing left, then. ...but this may depend on environmental conditions. this must depend on average environmental temperature, right? Might dinosaur specimens in Antarctic or Arctic regions have experienced signif…

>65 million years would mean 130 halvings. Basically nothing left, then

Nah, we just need to find roughly 2^130 dinosaur cells, and the rest is statistics...

Re: Possible dinosaur DNA has been found

#115

Post by EmilioMartinez »

colinnordin wrote: post #101

Assuming we had millions of 3D-scans of different kinds of animals and their full DNA sequence. Wouldn't it be interesting to try to use generative ML methods to generate a dinosaur DNA based on a 3D model?

Sounds like you want to make dinosaur-shaped dogs

Re: Possible dinosaur DNA has been found

#116

Post by Robotbeat »

jerzyt wrote: post #102
Robotbeat wrote: post #59

Earlier quoted context omitted.

What does half life of 500,000 years mean? Does that mean any given gene will, on average, split every 500,000 years? Or become unusable in 500,000 years? 65 million years would mean 130 halvings. Basically nothing left, then. ...but this may depend on environmental conditions. this must depend on average environmental temperature, right? Might dinosaur specimens in Antarctic or Arctic regions have experienced signif…

You raise a very good question. Unlike C14 dating, where the halflife is independent of environmental conditions, DNA is a chemical molecule, whose decomposition is a chemical reaction, dependent on exposure to time, temperature, pressure, light, and chemistry of the environment. I was hoping the article would explain why the conditions would be so favorable to make it possible.

Right. There must have been trillions of dinosaurs over the eons. Perhaps some individuals were buried in areas with colder conditions and chemical preserving agents. It may take a long time for us to find out.

Re: Possible dinosaur DNA has been found

#118

Post by masonic »

stanfordkid wrote: post #58
thaumasiotes wrote: post #50

Earlier quoted context omitted.

> It would be a reasonable thing to attempt with today’s technology, but it would be a serious R&D project. Dinosaurs have enough cultural prestige that it would make total sense to do it as a vanity project if the technology is there. Similar to turning lead into gold -- there's enough cultural meaning built up around it that someone should do it before it really makes sense in a vacuum.

A project like this could be the space race of our epoch!

I could see Elon Musk funding a Jurassic Park kind of effort to re-create dinosaurs... just to be the first to taste a dinosaur-egg omelette.

Re: Possible dinosaur DNA has been found

#120

Post by gnramires »

Robotbeat wrote: post #86
gnramires wrote: post #85

Earlier quoted context omitted.

Not sure where his 500k years figure comes from. A cursory search gives 521 years: https://www.nature.com/news/dna-has-a-521-year-half-life-1.1... Chemical decay tends to follow Arrhenius equation: https://en.wikipedia.org/wiki/Arrhenius_equation#Equation so indeed a difference of maybe 40C should lead to a difference in half life of about 20-30%. I think about 30 half lives (~10^-9 degradation factor) should be the…

Looks exponential to me. After all, the Arrhenius equation (whose constants seem different here than your earlier assumptions) is exponential.

Oh yes, I definitely messed up my calculations. Half life is (inversely) proportional to the reaction rate itself I guess (I were associating it with the exponent, because half life is usually in the exponent), so the half life itself would be proportional to exponential reciprocal of temperature (e^(a/T)).

This means significant differences in HL for minor temperature variations under e.g. Arrhenius model (consistent with your graph I think). To extrapolate it some parameters need to be estimated though, which sounds interesting, I'll get around to that later...

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