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At Big Think: Can we predict evolution?

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We can successfully predict the future arrangements of matter based on knowledge of the laws of physics that govern the interactions between particles. When too many particles exist to make detailed predictions about individual particles, we can use statistical physics to predict generally true and reliable outcomes of the larger system of particles. The 2nd law of thermodynamics provides us with a familiar example of outcomes based on statistical physics. If the future forms of living organisms are predictable, it will likewise be due to the ensemble of their systems of particles obeying fundamental laws of physics. “Evolution” is not a “law of physics” that is independent of or supersedes other known laws of physics.

Organisms respond in similar ways to similar circumstances.

KEY TAKEAWAYS

  • Evolution has long been viewed as a largely unpredictable process, influenced by chaotic factors like environmental disruptions and mutations. 
  • However, researchers have demonstrated cases in some organisms of “replicated radiation,” in which similar sets of traits evolve independently in different regions. Now, researchers report the first evidence for replicated radiation in a plant lineage. 
  • As biology learns more about phenomena like replicated radiation, we might be able to predict the course of evolution.

Evolution has a reputation for being unpredictable, yet orderly. With mutations and the environment playing huge roles, it seems that predicting which species will evolve which traits is much like guessing the roll of a single die with millions of faces. 

However, in some cases, researchers have found that the die rolls the same way again and again. A combination of separate organisms’ natural development and the environmental pressures placed on them can create very similar forms, or ecomorphs. Researchers call this phenomenon replicated radiation. (Sometimes, the term adaptive radiation is used synonymously.)

In a new paper published in the journal Nature Ecology & Evolution, an international group of researchers demonstrated that a plant lineage living in 11 geographically isolated regions independently evolved new species with similar leaf forms. This marks the first example of replicated radiation in plants, and the groundbreaking research gives us more insight into the possible future workings of evolution. 

Note: Reason suggests that the development of “similar leaf forms” stems from the fact that they all started from the same “plant lineage.” Furthermore, reason suggests that the original plant lineage had a built-in genomic variability that allowed the variant leaf forms to dominate when environmental pressures favored that form.

evolution
Credit: Annelisa Leinbach / Big Think

The article continues: Different species of Oreinotinus [Viburnum] have different types of leaves. Simply put, some have a large, hair-covered leaf, and others have a smaller, smooth leaf. Originally, experts postulated that both leaf forms evolved early in the group’s history and then dispersed separately through various mountain ranges, carried perhaps by birds. But the distribution pattern of the species, combined with the striking differences in leaf traits, gave researchers an ideal system to explore the possibility that these leaf forms evolved independently across different regions. In other words, they could explore whether this was a case of replicated radiation.

If replicated radiation is occurring, the researchers would expect two key results. First, species in the same area should be more closely related to each other than to species in different regions. Second, similar leaf traits should be present in most areas, but they should evolve independently of one another.

Turning over the same leaf

As Oreinotinus diversified, four major leaf types evolved independently from an ancestral leaf form. The four forms varied in size, shape, margin — that is, whether the edge of the leaf is smooth or toothed — and the presence of leaf hairs. The study grouped the leaves into four types. The researchers also backed up their assessments with a statistical analysis based on these characteristics. 

Nine of the 11 areas harbor at least two leaf forms; four areas include three forms; and one, Oaxaca, is home to four. Based on simulations and models, the authors rejected the simple evolutionary model in which the leaf forms evolved before the species dispersed. They also found that chance alone does not likely explain why nine areas of endemism host two or more leaf forms. Based on these lines of evidence, the team concluded that leaf forms evolved separately within multiple regions. The leaf morphs did not originate early in Oreinotinus evolution. Rather, as different lineages diversified within different areas, each lineage “traversed the same regions of leaf morpho-space.”

So what is this clade telling us when it evolves different leaf forms? As it turns out, different leaves provide different advantages that suit particular climate niches. For example, the smaller leaves would allow more precise thermoregulation — the leaf won’t get too hot or too cold as the weather changes. On the other hand, large leaves would be better for lower-light, frequently cloudy environments, because they improve light capture and make photosynthesis more efficient. So the different leaf ecomorphs are adapted to specific sets of subtly different but often adjacent environmental niches.

The future of evolution

Researchers can now add Oreinotinus to an exclusive list of other groups of organisms known to have undergone replicated radiation, such as Anolis lizards in the Caribbean, cichlid fishes in African rift lakes, and spiders in Hawaii.

With a plant on the list, evolutionary biologists know this is not a trend exclusive to animals isolated on islands, where most of the other examples come from. Like island archipelagos, the cloud forest environments of Oreinotinus are separate from one another. A plant example will help evolutionary biologists pinpoint the broad circumstances under which we can make solid predictions about evolution.

Whether it’s Darwin’s finches, Oreinotinus, or a group of sugar-hungry E. coli, we are all subject to the mysterious workings of evolution. But perhaps, as a diverse set of research groups work to tackle the problem, the mystery will fade. As Michael Donoghue, a co-corresponding author of the Oreinotinus  study, said in a statement, “Maybe evolutionary biology can become much more of a predictive science than we ever imagined in the past.”

Full article at Big Think.

Predictive success alone does not guarantee the success of a theory of how nature works. Additional consequences of a theory must also make sense and not contradict established laws of nature. Naturalistic evolution still contradicts the principle that natural causes will on average degrade the information content (loss of functional complexity) of a system over time.

Comments
Alan Fox @250, Wikipedia articles are rarely a reliable source--I wouldn't recommend using them. But you're now diverging from my challenge regarding experimental (rather than conjectural) evidence of the half-life of DNA in ideal realistic environments. Note that I'm not claiming DNA half-life as a viable dating method, but I am claiming that there's no experimental evidence for DNA being able to survive in a scientifically useful form tens of thousands let alone millions of years. A related question is "What constitutes the minimum useful fragment length of DNA?" Certainly not one or two base pairs, right? And then there's DNA deamination to consider as well. -QQuerius
September 17, 2022
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The Neanderthal Genome Project https://en.m.wikipedia.org/wiki/Neanderthal_genome_project A useful gateway to much primary literature.Alan Fox
September 17, 2022
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Jerry @246, Nice. And do these remind you of anything? https://www.youtube.com/watch?v=l7HTA6-bPy4 Notice that they're called "living fossils." -QQuerius
September 16, 2022
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Alan Fox @238,
Yes, I suspect that’s right. You think you’ve proved a point.
Well, thank you. And thank you again for at least providing the links to the two relevant studies. I found them very interesting.
However, it’s evidence, not proof, that applies in science.
Complete agreement with you on that. Unfortunately, the findings are rarely qualified in an academic environment, promoting a false sense of scientific confidence to students rather than characterizing the evidence as not more than evidence leading to our theories. Students should understand that all scientific theories change and science progresses as the resistance to old theories collapses in light of new evidence. For example, as reported in Live Science in March 2020, a study published in Natural Geoscience, researchers lead by geoscientist Benjamin Johnson reported that they have compelling evidence from isotope ratios regarding conditions on the early earth. It reads
What did Earth look like 3.2 billion years ago? New evidence suggests the planet was covered by a vast ocean and had no continents at all.
Maybe new discoveries will reveal problems with Johnson’s work—who knows. But the idea is not to immediately reject evidence that runs counter to prevailing theories.
DNA fragments long enough to enable phylogenetic analysis are extractible after hundreds of thousand years in suitable samples.
The “hundreds of thousands of years” is conjecture. It could just as easily and legitimately be argued that these samples are more likely to be thousands of years old instead, especially since there’s no evidence of the speculated unknown mechanism to preserve this DNA for that extraordinary length of time. The same study reported a factor of 6 between the half-life of plant versus animal DNA, and speculates why this might be the case—again something that could and should be subjected to experimental validation or falsification.
Previous claims for multiple millions have been shown to result from contamination. The half-life figure is consistent with that.
Exactly. And when these discoveries were made, they were accepted and published. The skeptical scientific conversation that followed presumably resulted in experimental data confirming the contamination of the samples, again not simply rejecting the previous data on philosophical grounds.
I’m still unclear as to what your point is precisely and how it differs from what I’ve summarised in this comment.
Then let me remind you of my previous challenges, to which you asked me to pick one of them for you to follow up on. To your credit, you did so. And it turns out that the 20-30 million year-old DNA from insects in amber claim was later shown (I presume) to be due to contamination. The DNA could in no way be preserved for 20-30 million years. Even the supposed “complete” sequencing of 430,000 year old Neanderthal DNA should be highly suspect as well. -QQuerius
September 16, 2022
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AF, I have put on the table what you failed to. That should be enough for Q. And you are still evading the point raised by Lehninger's heirs. KFkairosfocus
September 16, 2022
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Looks like something out of the ancient past. Maybe from Cambrian. https://upload.wikimedia.org/wikipedia/commons/2/25/990804-Chabahar-IMG_6019-2.jpgjerry
September 16, 2022
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Tree rings can give dating patterns to what 10’s kyr?
I wondered whether my mention of tree ring overlap would be misunderstood. The reason DNA fragments can be useful is sequences overlap, allowing reconstruction of longer sequences.Alan Fox
September 16, 2022
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Ancient DNA fragments can persist for several hundred thousand years depending on the immediate environmental conditions. Longer claimed dates have not stood up to scrutiny. Phylogeny confirms this. Focus, KF. If you disagree with that, fine. Say so and say why and we can have an exchange of view. But, focus.Alan Fox
September 16, 2022
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Q, I think the just above may be of interest, giving some relevant half lives and linked estimates. Of course, incidence of radioactive damage and damage from environment would depend on many factors. KF PS, Wikipedia on GC-content of DNA throws in a monkey wrench, in its confessions:
DNA with low GC-content is less stable than DNA with high GC-content; however, the hydrogen bonds themselves do not have a particularly significant impact on molecular stability, which is instead caused mainly by molecular interactions of base stacking.[2] In spite of the higher thermostability conferred to a nucleic acid with high GC-content, it has been observed that at least some species of bacteria with DNA of high GC-content undergo autolysis more readily, thereby reducing the longevity of the cell per se.[3] Because of the thermostability of GC pairs, it was once presumed that high GC-content was a necessary adaptation to high temperatures, but this hypothesis was refuted in 2001.[4] Even so, it has been shown that there is a strong correlation between the optimal growth of prokaryotes at higher temperatures and the GC-content of structural RNAs such as ribosomal RNA, transfer RNA, and many other non-coding RNAs.[4][5] The AU base pairs are less stable than the GC base pairs, making high-GC-content RNA structures more resistant to the effects of high temperatures. More recently, it has been demonstrated that the most important factor contributing to the thermal stability of double-stranded nucleic acids is actually due to the base stackings of adjacent bases rather than the number of hydrogen bonds between the bases. There is more favorable stacking energy for GC pairs than for AT or AU pairs because of the relative positions of exocyclic groups. Additionally, there is a correlation between the order in which the bases stack and the thermal stability of the molecule as a whole.[6]
kairosfocus
September 16, 2022
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AF, more general dismissiveness and distractors. As clipped, they confirm presence of thermally linked degradation rates but say after a time for fragmentation on their model, it seems to effectively stop [''slows"]. The latter would imply, only partial vulnerability to activation processes leading to exhaustion. But if they had solid reasons for that they would NOT be talking about poorly understood dynamics, they would announce ta-da this is the part that breaks down, why. Obviously, they don't: " . . . the dynamics of DNA degradation are still poorly understood." This sounds like floundering. KF PS, Let's observe a generally related discussion on stability: https://www.pnas.org/doi/10.1073/pnas.95.14.7933
High-temperature origin-of-life theories require that the components of the first genetic material are stable. We therefore have measured the half-lives for the decomposition of the nucleobases. They have been found to be short on the geologic time scale. At 100°C, the growth temperatures of the hyperthermophiles, the half-lives are too short to allow for the adequate accumulation of these compounds (t1/2 for A and G ? 1 yr; U = 12 yr; C = 19 days [0.05202 y]). Therefore, unless the origin of life took place extremely rapidly (<100 yr), we conclude that a high-temperature origin of life may be possible, but it cannot involve adenine, uracil, guanine, or cytosine. The rates of hydrolysis at 100°C also suggest that an ocean-boiling asteroid impact would reset the prebiotic clock, requiring prebiotic synthetic processes to begin again. At 0°C, A, U, G, and T appear to be sufficiently stable (t1/2 ? 106 yr) to be involved in a low-temperature origin of life. However, the lack of stability of cytosine at 0°C (t1/2 = 17,000 yr) [--> after 10 X t1/2, we are looking at very little left, 170 ky, after 100, 1.7 MY, that's 1 part in 2^100 ~ 1.3*10^30 i.e. you would need millions of moles to have anything left] raises the possibility that the GC base pair may not have been used in the first genetic material unless life arose quickly (<106 yr) after a sterilization event. A two-letter code or an alternative base pair may have been used instead.
Translation, we have a serious problem projecting to dozens of MY. PPS, we still have the Lehninger problem, and you tried a double down above:
"The information in DNA is encoded in its linear (one-dimensional) sequence of deoxyribonucleotide subunits . . . . A linear sequence of deoxyribonucleotides in DNA codes (through an intermediary, RNA) for the production of a protein with a corresponding linear sequence of amino acids . . . Although the final shape of the folded protein is dictated by its amino acid sequence, the folding of many proteins is aided by “molecular chaperones” . . . The precise three-dimensional structure, or native conformation, of the protein is crucial to its function." [Principles of Biochemistry, 8th Edn, 2021, pp 194 – 5. Now authored by Nelson, Cox et al, Lehninger having passed on in 1986. Attempts to rhetorically pretend on claimed superior knowledge of Biochemistry, that D/RNA does not contain coded information expressing algorithms using string data structures, collapse. We now have to address the implications of language, goal directed stepwise processes and underlying sophisticated polymer chemistry and molecular nanotech in the heart of cellular metabolism and replication.]
PPPS, Tree rings can give dating patterns to what 10's kyr? That DNA fragmentation overlaps suggests there is NOT an exhaustion of a particularly vulnerable subset of bonds [contrast, decay of C where dramatically shorter lifespan gives reason to look for it as low hanging fruit . . . taking the same 100 C to 0 C ratio on t1/2, about 327k:1, we are looking at A, G with 0C t1/2 ~ 300ky, T 3 MY], and homology is part of circular arguments, down to circular redefinition on imposition of macroevo as baseline.kairosfocus
September 16, 2022
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What you need, is to show directly observed evidence similar to, as I pointed out, up to 500k spontaneous changes per day in a cell, leading to a significant repair process. KF
You are missing the point. Do you know anything about tree ring dating? Samples overlap. DNA fragments overlap. Homology exists.Alan Fox
September 16, 2022
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PPPS, Nor is it just DNA, the discovery of apparent preservation of soft tissue samples such as collagen in dinosaur bones out to the typical 65 MY etc is a similar serious question.kairosfocus
September 16, 2022
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AF, there goes that elephant, hooonk. Yes they say in effect activation processes fail, on samples dated on their timeline. That, embeds endless assumptions. What you need, is to show directly observed evidence similar to, as I pointed out, up to 500k spontaneous changes per day in a cell, leading to a significant repair process. KF PS, your first link says:
The persistence of DNA over archaeological and paleontological timescales in diverse environments has led to a revolutionary body of paleogenomic research, yet the dynamics of DNA degradation are still poorly understood. We analyzed 185 paleogenomic datasets and compared DNA survival with environmental variables and sample ages. We find cytosine deamination follows a conventional thermal age model, but we find no correlation between DNA fragmentation and sample age over the timespans analyzed, even when controlling for environmental variables. We propose a model for ancient DNA decay wherein fragmentation rapidly reaches a threshold, then subsequently slows. The observed loss of DNA over time may be due to a bulk diffusion process in many cases, highlighting the importance of tissues and environments creating effectively closed systems for DNA preservation. This model of DNA degradation is largely based on mammal bone samples due to published genomic dataset availability. Continued refinement to the model to reflect diverse biological systems and tissue types will further improve our understanding of ancient DNA breakdown dynamics . . . . Previous studies have identified age as the key critical predictor of deamination (60), but our finding is in line with predictions of a time-dependent hydrolytic process where activation energy is achieved more often at higher ambient temperatures. A rate of deamination can be calculated for any sample with a known age and partial conversion of exposed cytosines (Figure 3). The resulting rates vary widely and show a strong correlation with temperature (r2 = 0.279; P = 1.23 × 10?12). In sum, deamination is a time-dependent process heavily modulated by temperature. When analyzing DNA fragmentation, however, we found that precipitation and thermal fluctuation were strongly significant predictors (multiple r2 = 0.202; precipitation P = 0.0025; temperature fluctuation P = 6.18 × 10?8) but that age was not significantly correlated with the degree of fragmentation (P = 0.77), even when controlling for environmental conditions. We also find that in addition to the humidity and thermal fluctuation pattern, the degree of DNA fragmentation correlates strongly with base compositional biases. Specifically, datasets dominated by short fragments are significantly depleted of weakly-bonded nucleotide motifs (P = 6.79 × 10?12, r2 = 0.253; Figure 2), indicating that DNA breakdown follows predictable patterns with regard to microenvironment and nucleic acid biochemistry. Relatedly, we detected a histone-associated fragmentation bias (22) in the majority of our samples (n = 112), and we find that annual mean temperature is strongly associated with the intensity of this pattern (P = 1.2 × 10?5, r2 = 0.16; Figure 2). Specifically, DNA breakdown in colder environments appears to more faithfully reflect cellular architecture and the in vivo genome context, whereas breakdown in warmer conditions is much less discriminant.
That boils down to, we are baffled. PPS, similarly, you have Lehninger's heirs to answer.kairosfocus
September 16, 2022
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So I think I’ve proved my point in @102, right?
Yes, I suspect that's right. You think you've proved a point. However, it's evidence, not proof, that applies in science. DNA fragments long enough to enable phylogenetic analysis are extractible after hundreds of thousand years in suitable samples. Previous claims for multiple millions have been shown to result from contamination. The half-life figure is consistent with that. There is no controversy about ancient DNA and work will continue as long as it is fruitful. I'm still unclear as to what your point is precisely and how it differs from what I've summarised in this comment.Alan Fox
September 15, 2022
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Alan Fox, First off, thank you for finding the references. Temporal patterns of damage and decay kinetics of DNA retrieved from plant herbarium specimens
We investigated patterns of DNA fragmentation and nucleotide misincorporation by analysing 86 herbarium samples spanning the last 300 years using Illumina shotgun sequencing.
The fit to a log/exponential curve (linear on a log scale) is expected for specified temperatures and other environmental conditions. Preservation through drying might be explained by the removal of water from the plant. Environmental DNA shedding and decay rates from diverse animal forms and thermal regimes This study is irrelevant to our discussion due to the aquatic environment of eDNA that results in a half life measured in hours. A new model for ancient DNA decay based on paleogenomic meta-analysis
The persistence of DNA over archaeological and paleontological timescales in diverse environments has led to a revolutionary body of paleogenomic research, yet the dynamics of DNA degradation are still poorly understood. We analyzed 185 paleogenomic datasets and compared DNA survival with environmental variables and sample ages. We find cytosine deamination follows a conventional thermal age model, but we find no correlation between DNA fragmentation and sample age over the timespans analyzed, even when controlling for environmental variables.
This interesting study mentions both fragmentation and deamination. I was surprised that it didn't also mention background radiation, however. The expected patterns seem to hold for samples 10,000 years old and less as with Bronze Age Europeans and Neolithic Aegeans, but my biggest objection is that it accepts paleontological time scales, working backwards to what the rate of DNA disintegration MUSTA been and speculate on possible causes. The result is a lack or correlation with time when considering fragmentation. This is highly suspect. In any case, the "The complete genome sequence of a Neandertal from the Altai Mountains" (2013) and "Researchers Sequenced 430,000-Year-Old DNA From Neanderthal" (2015) remain highly suspect in light of the studies you provided! In my opinion, the first study, published by the Royal Society, is the most interesting and they admit being puzzled by some of the data they obtained and attempt to speculate on why. The big takeaway is that after initial decomposition, DNA is observed to decay at a rate largely dependent on age and is not compatible with claims of paleogenomic finds and presumed dating. After millions of years of exposure to temperature and background radiation, such DNA should be by now have been turned into powder--or the dating is wrong. So I think I've proved my point in @102, right? -QQuerius
September 15, 2022
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KF
You know you need to come up with a reasonable empirically warranted decay curve for DNA
https://academic.oup.com/nar/article/45/11/6310/3806656 Follow the link. Read the paper. Check the references.Alan Fox
September 15, 2022
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What’s the specific, not hurl an elephant, reasonable decay pattern and curve, backed by what empirical evidence.
I repeat: https://academic.oup.com/nar/article/45/11/6310/3806656Alan Fox
September 15, 2022
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F/N: As a start, here is an estimate https://garmaonhealth.com/wp-content/uploads/2017/05/Celluar-DNA-Damage.png This estimates up to 500 k DNA modification events per cell PER DAY. Countered by active repair mechanisms but of course such can lead to cancer, aging effects and cell death. Now, under reasonable circumstances, where does that go with death, decay etc on the table? What's the specific, not hurl an elephant, reasonable decay pattern and curve, backed by what empirical evidence. KFkairosfocus
September 15, 2022
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AF, evasion as usual. You know you need to come up with a reasonable empirically warranted decay curve for DNA, and particularly for why -- independent of ideological impositions of evolutionary materialistic scientism -- anyone should take seriously claims of sufficient survival for dozens of MY. KF PS, as we are still on the topic of DNA, you were last challenged to address why you have tried to dismiss the point that it expresses coded information in part expressing algorithms, and do so i/l/o this from Lehninger's literary heirs [bearing in mind the weight of that legacy]:
"The information in DNA is encoded in its linear (one-dimensional) sequence of deoxyribonucleotide subunits . . . . A linear sequence of deoxyribonucleotides in DNA codes (through an intermediary, RNA) for the production of a protein with a corresponding linear sequence of amino acids . . . Although the final shape of the folded protein is dictated by its amino acid sequence, the folding of many proteins is aided by “molecular chaperones” . . . The precise three-dimensional structure, or native conformation, of the protein is crucial to its function." [Principles of Biochemistry, 8th Edn, 2021, pp 194 – 5. Now authored by Nelson, Cox et al, Lehninger having passed on in 1986. Attempts to rhetorically pretend on claimed superior knowledge of Biochemistry, that D/RNA does not contain coded information expressing algorithms using string data structures, collapse. We now have to address the implications of language, goal directed stepwise processes and underlying sophisticated polymer chemistry and molecular nanotech in the heart of cellular metabolism and replication.]
kairosfocus
September 15, 2022
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@ KF The significance of that remark at 231, which I don't disagree with per se is?Alan Fox
September 15, 2022
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AF, yes it would but a key driver is activation processes that are temp sensitive. DNA is highly endothermic and metastable, a pattern that is similar to many medications, explosives and many other organic chem derived things. KFkairosfocus
September 15, 2022
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The a href="https://doi.org/10.1093/nar/gkx36">paper I refer to in 229, interesting in itself, has a list of citations that illustrate the breadth and usefulness of work on DNA fragments. A point made in all of the above is decay rate is dependent on many more variables than just age.Alan Fox
September 14, 2022
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https://academic.oup.com/nar/article/45/11/6310/3806656Alan Fox
September 14, 2022
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https://onlinelibrary.wiley.com/doi/full/10.1002/edn3.141Alan Fox
September 14, 2022
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https://royalsocietypublishing.org/doi/10.1098/rsos.160239#:~:text=We%20found%20an%20exponential%20decay,rate%20estimated%20for%20ancient%20bones.Alan Fox
September 14, 2022
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Querius:
So what’s the experimentally measured half life of DNA extracted from animals in caves or other even more ideal environments such as permafrost?
I just saw this. Off-hand I don't know whether any research has been done to establish rates of decay over time in samples that contain DNA, other than the work on moa bones.Alan Fox
September 14, 2022
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But that's different, Kairsfocus! It's a scientific appeal to the bandwagon! LOL Most drug companies test experimental drugs, typically large molecules, in silico. I've had the opportunity to play with one of these, viewing molecular bonds breaking as I dial up the temperature. I'm sure that the same could be said of adding in background radiation (which includes the bones and dentin typically accessed for archaic DNA samples). My question to Alan Fox remains unanswered:
So what’s the experimentally measured half life of DNA extracted from animals in caves or other even more ideal environments such as permafrost?
-QQuerius
September 14, 2022
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PS, do I need to remind of the rule of thumb that for room temp, activation energy decay processes double their rate for every 8 degrees C increase? Which instantly tells us for any reasonable temperature, there is an ongoing spontaneous breakdown.kairosfocus
September 14, 2022
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AF, appeal to the bandwagon. The issue is not opinion or popularity but thermodynamics. Even medicines have expiry dates and instructions to refrigerate. What is that telling us? KFkairosfocus
September 14, 2022
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Yes, really. I don't see anyone but you talking as if the survival of DNA fragments is controversial. Early attempts at recovery using PCR techniques were bugged by contamination. Now researchers are more careful. That's progress.Alan Fox
September 13, 2022
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