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Every neuron potentially has a different genome than those it's connected to (scientificamerican.com)
177 points by molecule on May 11, 2017 | hide | past | web | favorite | 125 comments

Coming from a bioinformatics background this is really, really surprising to me. I knew there was always a chance of individual cells diverging from the shared genome but we always considered that a hallmark of cancerous, abnormal growth.

Thinking that you could have a trillion unique variations of the genome significantly ups the computational complexity of simulating an organism by a frightful order of magnitude. We are so much further from understanding biological systems than we ever thought.

That's been the main lesson from the modern era of sequencing, genomics, and bioinformatics - we haven't learned nearly as much as we have unlearned.

Agreed. That's like orders of magnitude orders of magnitude.

Definitely surprising, although in one of those hindsight realizations -- c.elegans has a specific consistent function for each cell and each cell under normal development.

If 300+ cells of a worm can be that well orchestrated, of course slightly more complex creatures could. Evolution is a series of slight successes.

What if the cells of the brain have their own genome because each one of the billions of cells has a near specific specialized function.

Could cellular function be that precise? Each micron of tissue the result of specific evolutionary pressures?

I suspect that it's much like the immune system. For example, antibody diversity is "generated by DNA rearrangements during B-cell development".[0] And:[1]

> In another parallel with the immune system, cadherin-related neuronal receptors (CNRs) are diversified synaptic proteins. The CNR genes belong to protocadherin (Pcdh) gene clusters. Genomic organizations of CNR/Pcdh genes are similar to that of the Ig and TCR genes. Somatic mutations in and combinatorial gene regulation of CNR/Pcdh transcripts during neurogenesis have been reported.

So as with evolution, more-or-less random variation generates diversity in the developing nervous system. And then there's selection.

0) https://www.ncbi.nlm.nih.gov/books/NBK27140/

1) https://www.ncbi.nlm.nih.gov/pubmed/12558794

> What if the cells of the brain have their own genome because each one of the billions of cells has a near specific specialized function.

That's the opposite of my interpretation -- it goes to show that even in the face of inevitable statistical noise, biological systems are incredibly fault-tolerant and durable. And furthermore, a neuron is just a neuron. It's unlikely that the genomic differences in a genius's neurons are significant compared to the overall genetic average which gave rise to a certain structure, certain proteins being more common, etc.

An interesting hypothesis, but difficult to reconcile with the surprisingly successful history of hemispherectomy [1]. Unless, perhaps, many unique neurons still serve nearly identical functions, despite their differences? Perhaps their uniqueness is a defense against disease, rather than functional specialization?

I don't mean "functions" in the sense of classic neuroscience, like specialized regions of the brain; I am using it as a very generic term, for lack of a better one.

[1] https://en.wikipedia.org/wiki/Hemispherectomy

> Could cellular function be that precise? Each micron of tissue the result of specific evolutionary pressures?

If that's what the data says.

It's probably an emergent quality from a set of simple rules being iterated. You can do a lot with a very very little if you're procedural about it.


It's a pretty fascinating result, and it almost seems obvious in hindsight -- a statistical result of entropy which has profound implications for anti-aging research.

The biggest takeaway for me is that physically isolated genetic diseases and asymmetries which manifest during an organism's growth may not be contained whatsoever in the organism's zygotes / passed along to its offspring (not that this was an impossible result before, but I suspect there is a higher probability of genetic independence than previously thought.)

I would love to see comparisons of the standard deviations of "healthful" individuals to less healthy individuals. I would imagine that some genomes are far better at protecting themselves than others.

My own hypothesis is that maybe our memories are stored in DNA in our brain cells. This article made my hypothesis a little more likely... Also, read the article "Microsoft experiments with DNA storage: 1,000,000,000 TB in a gram" at Ars Technica. https://arstechnica.com/information-technology/2016/04/micro...

You hypothesis physically implausible - for starters, the speed at which memories are made and recalled is much, much faster than the timescale in which "writing" and "reading" of DNA happens.

While you can encode a lot of data in arbitrary arrangements of a molecule (just as you can encode a lot of data in e.g. arbitrary arrangements of magnetic polarity in a dense material) if you have the right tools to do that, our cells have different tools specialized to do different processing on DNA molecules. There's no evidence to suppose that these changes in DNA are somehow controllable by external factors as opposed to random variations, and there's no evidence to suppose that these changes in DNA are readable in any other way than the usual creation of proteins required for functioning of the cell.

Does your memory seem like it's big enough to require that much storage...?

Mine doesn't.

The more we learn, the less we know.

More like, the more we realize how little we actually knew before.

The more we learn, the more our DNA knows.

I suspect that we'll find this wherever there's a process involving massive generation of somatic diversity, plus functional selection. The immune system. The nervous system. Where else might that be useful?

This doesn't necessarily change anything about computing neural nets. You need to view the genomic variation as representing the complexity of each neural unit: its connections (in and out), it's propensity to fire, and function it operates by. The genome is just the code representing this information.

Basically, each node in a neural nets is unique akin to each neuron.

> you could have a trillion unique variations of the genome

It's not really as bad as it sounds. The vast majority of those small mutations must be in the non-coding and non-regulating zone, with no effects on the genome's functionality.

As the article mentions[1], it's an interesting line of study, but let's not jump to conclusions.

[1]: "[...] each neuron may harbor hundreds of somatic mutations. Given the long life span of neurons and their central role in neural circuits and behavior, somatic mosaicism represents a potential mechanism that may contribute to neuronal diversity and the etiology of numerous neuropsychiatric disorders." - http://science.sciencemag.org/content/356/6336/eaal1641

One major trend over the past 20 years has also been the realization that "non-coding" regions tend to be anything but, their effects are subtle and still being discovered.

Nevertheless, it is long being observed that for example in cancer most mutations are passenger mutations. And this is true even more if they come from non-coding regions.

Honestly, I am a bit surprised that you claim to have a bioinformatics background and are surprised about somatic variants. I mean, they are observed everywhere in NGS (and used on a daily basis for tracking pluripotent stem cell clonality and other things), there is not much surprising about it anymore.

My unfinished PhD dissertation was about the topological differences in metabolic pathways expressed by various cancer cell lines in contrast to healthy tissue as a means of targeting metabolic "choke points" for future drugs - I'm not surprised about the existence of somatic variants but I am looking back and realizing how many of us were taking the uniformity of our systems for granted. Even when modeling the differences in a rapidly mutating cancer we always treated the variants as collections of discrete mutations that were uniform across the cluster. Then again this was ten years ago and you couldn't even think of sequencing enough lines to get at a cellular resolution. This really makes me want to pick that back up.

This is an argued area, but I think most people would agree that LTRs, which make up the bulk of non coding regions, have effectively zero effect on functional selection. There are many regions which are non-coding which appear to be under selection and play functional roles, but (and this belief only changed after looking into the problem in some detail) most of the LTR regions have no effect.

Not sure why this _should_ be surprising, seeing as how multicellular organisms began as cooperative colonies of individuals.

Maybe? It's certainly the dominant theory but I wouldn't ascribe real truth to it. There are certainly species today that operate this way but there's no way to prove they represent the origin of multicellularity. There's no reason to even believe it happened only once.

Mystics have been talking about this sort of thing for ages. Perhaps you should look into some of those assertions to develop future investigative paradigms.

One of the fundamental techniques used by most varieties of mysticism is to make proclamations vague enough that they can be plausibly associated with any fact that is discovered later on. This is how mystics trick gullible people into believing that they have hidden knowledge. The trick is that these proclamations can't be used to make useful predictions; they only fit the data in hindsight.

You might want to look past the Deepak chopra types into the older mystery schools that don't solicit people's attention.

Such as?

Hermeticism and derivatives of Egyptian mystery schools make for some interesting reading, and can be approached through academic avenues of archaeological/anthropological studies rather than woo-woo books and blogs. I'm definitely not suggesting it as an alternative to using scientific methods.

I find hermeticim fascinating, but I don't really see the connection. Where is hermeticism talking about genomes and neurons?

If I direct you to particular texts or ideas, then not only would I be falling into the trap of saying 'you should check out this spiritual technology, dude,' you'd be missing out on the exploratory and imaginative process that necessarily precedes discovery and innovation.

I'm saying that people should keep using the scientific method to formalize and test their hypotheses, but that esoteric traditions offer some interesting and under-explored paradigms within which to hypothesize. I'm being deliberately vague here because I don't want to bias you.

I think you are being deliberately vague because you haven't anything except handwaving.

Theravada Buddhism.

Once the mystics show some reproducible data it might make sense to listen what they have to say.

I'm not much of a mystic myself, but there is something to be said for seeking inspiration from non-scientific sources.

Note that this doesn't (nor should it) prevent actual, hypothesis-driven scientific inquiry. It just means the original idea came from elsewhere. If you look back at the history of scientific discovery, this happens quite often.

Mysticism isn't trying to be a better science, any more than a guttering candle is trying to be a better laser pointer.

No two cells are ever genetically identical. Within a common hyper-mutable region, tandem repeats, the mutation rate is 10^-3 to 10^-5. There are over 10^5 tandem repeats in the genome, and therefore at least one mutation is expected for every cell division. Many other types of hyper-mutable regions exist in the human genome.

In this research they only examine one form of genetic variation, SNPs. These findings only reflect a small proportion of the somatic variation present in the body.

There is no real surprise in these results, but the data may nevertheless be useful!

(while most here understands CPU RAM RAII DRY etc., you might want to mentions that SNP means "single nucleotide polymorphism", which are mutations where just a single base pair differs.)

"A primary cause of somatic mutations has to do with errors during the DNA replication that occurs when cells divide—neural progenitor cells undergo tens of billions of cell divisions during brain development, proliferating rapidly to produce the 80 billion neurons in a mature brain."

Certainly there must be tens of billions of cell divisions to create all the neurons, but each neural progenitor cell would only divide 30-40 times, right?

I'm not surprised that there are mutations, but the number of mutations is remarkable to me, and seems like yet another evolutionary check on brain size that I hadn't considered (energy use, difficulty of birth, and difficulty of childhood being the more obvious ones).

>"Certainly there must be tens of billions of cell divisions to create all the neurons, but each neural progenitor cell would only divide 30-40 times, right?"

Surprisingly to most, this is not a mainstream opinion: https://www.ncbi.nlm.nih.gov/pubmed/25459141

I would guess the main reason is that it leads to major problems with the current model of cancer.

Thanks for the link. Very interesting stuff.

Also worth noting that there's a difference between mutation and cancer, although of course they're related. Just as mice and people get cancer at similar rates, so do elephants, which have many more cell divisions, but have more elaborate anticancer mechanisms (presumably because elephants lacking them died of cancer).

If you give humans 2^53 divisions (as in that paper) and elephants have ~100x the mass of humans, as a rough estimate they would require 2^60 divisions. So about 7 more divisions per stem cell to live as long as the usual human (they usually don't live that long).

Instead of "per stem cell" that should be 7 more divisions from the zygote.

For some of the cells, like neurons, that to a first approximation don't divide in adulthood, this seems true. But for things like blood cells that are constantly getting turned over, it seems like there would be a lot more opportunities for bad mutations in a larger creature (although as your link suggests, there seems to be some fairly strong defense against this).

Well, DNA is kind of Big Data. And everyone who worked with Big Data knows that there will always be all kinds of inconsistencies and errors.

Personally, I was always skeptical that all non-sex human cells share the same DNA, it's just statistically unbelievable that billions of cells each having billions of DNA pairs would have then equal. I expected something like 1% of cells to have mutations.

Now they say that it's 100% for neurons. Exact 100% number is also pretty sketchy from statistical standpoint.

Nobody ever said that all cells share 100% of DNA in the sense you're implying. It's obvious that DNA undergoes dynamic processes, some of which will result in lasting differences. The accumulation of errors is the basic mechanism for cancer, which has been recognised for decades.

But it was previously thought that such differences were detrimental to function (and health). There were some mechanisms for modifying cells' DNA, collectively known as "epigenetics", but these were reversible, at least in principle.

This adds another dimension of complexity, which biology already had plenty of. My favourite is the double- or triple-coding DNA: because DNA is read in triplets, there are three possible reading frames. Some organisms have evolved DNA that produces entirely different, but independently useful proteins on two or even all three reading frames of the same DNA. Talk about efficiency...

Do you have any links for the last paragraph? I know that there can be two gene encoded in reverse in bacteria but have no knowledge of any frame-shifted translations?

About the second paragraph: well, it was not really thought that differences are always detrimental to health, and there is quite a number of variant prioritization tools out there that try to find those variants that are causal compared to all the silent/no-effect mutations (mostly for comparing humans but also somatic).

Look at it from the other end - if there are on average a 1000 difference between two neurons, and a difference can be encapsulated by a single bit you'd have 2^1000 variants - you'd expect to have to look at 2^500 neurons to find a duplicate. And a difference is probably more than one bit.

Now they say that it's 100% for neurons. Exact 100% number is also pretty sketchy from statistical standpoint.

What class of problem is searching for duplicates or uniqueness among a set of billions of items? If it is a tractable problem, what is the most effective algorithm?

Sometimes I wonder how so much complexity and co-dependency has evolved on earth in such little time. Most estimates I've read say that we're likely within an order of magnitude of 100 trillion generations deep from the universal common ancestor at this point. That sounds like a lot, but not really. If you took 30 four sided die, you'd have to roll them a million trillion times to have a good shot at getting any specific permutation.

How many 'die rolls' does it take to get a selective feature to emerge in an organism? If you do a google image search for 'camouflage bugs', you'll find some brain-bending examples. There's clearly a selective advantage for some of those 'configurations', but how many generations would it take for each genetic mutation required to make a lichen katydid or an orchid mantis to converge?

I don't think dice are a good comparison, as each roll is a new "state", knowing nothing about the previous. Vs. evolution which has kind of a feedback loop which influences future output.

Why do you assume that progress only happens at the interface between generations? If that were the case, human beings would be at a huge disadvantage, given that we wait ~20 years or so before reproducing.

The longer we wait before reproducing, the more intelligent the decision to reproduce will be -- which is what determines the genome of the resulting offspring.

> There's clearly a selective advantage for some of those 'configurations', but how many generations would it take for each genetic mutation required to make a lichen katydid or an orchid mantis to converge?

If you pose the question like that with the posteriori knowledge in mind, then yes, these configurations are highly improbable. I think another question that could be asked is: How many generations would it take for some mutations to produce some camouflage effect in some of the millions of existing species? Surely some mutations​ that produce camouflage effects will happen.

Some changes can happen really quickly too. If you look at breeders of fancy pigeons or fish, they can do incredible things in a relatively small number of generations. Of course, breeders are generally much more selective than nature, but it gives you a lower bound on what is possible.

Wait, the headline says no two alike, while the body text seems to go no further than that every cell is potentially different. What is it? If the somatic mutation rate is >1/neuron, that's a real surprise to me, but if it's "there's plenty of mosaicism and it makes a real difference", then not.

Good catch. We've changed the title above to a representative phrase from (I think) the paragraph you're referring to.

OTOH Real_S comments that the rate is indeed >1. So huh, I learned something.


the more closely you look, the more obvious it becomes that this is the rule rather than the exception. I would be somewhat surprised if children have functional mutations rampant between neurons, and I suspect that some fraction of this is artifactual. But I have no doubt (does anyone?) that some degree of somatic mosaicism is the rule. About the only cells that tend to hang around much longer than neurons are blood stem cells, and as soon as you look closely at those, it's all but unavoidable.

God damn it, that Science paper is piss weak even for a Science paper. It's yet another consortium advertisement. Meanwhile mapping of somatic mutations in blood progenitors has been happening for a decade.

This exactly. Somatic variants are one of the most common things around.

I always wonder why HN will almost never upvote a general informatics research article instead of a good review and with other fields of research it is the other way around where a review would be much better suited.

Isn't this old news? The reason is vaguely similar to the DNA modification that happens in the immune system: recognition of self. In this case, the goal is to avoid loopback connections. Nerve cells that touch themselves are bad. By DNA modification, the cells get different surface protein and are thus able to avoid connecting to themselves.

I wonder if this is involved in storing information in the brain.

Neurons practically never die, so the DNA itself will not directly reflect what a decades old braincell stores, though some mutations might influence how or if at all a certain neuron stores something. But since these mutations are random they are closer to defects (the article draws a connection to psychiatric diseases) than features.

But DNA can also be methylated, which is something that also happens in neurons and might be involved with actual memory.

And if you ever want to digitize a brain, then you might have to grab the DNA of 100 billion neurons as well, and there straightforward mutations are easier than just a somewhat transient methyl group here and there.

I read a research paper a couple years ago making an argument that neurons were using DNA as a kind of Turing tape for information storage. Very interesting but I can't seem to find it now.

Initial randomization of neural network weights?

Thought the same. Or computation, or any other sort of functional benefit...

Every single microprocessor in every computer is unique in its own way (small errors in production). It doesn't mean we can't compute with them, nor that the variation is useful or relevant.

This is an incredibly reductive analogy. The whole point of the article is that the neuronal variation does seem to be relevant.

It seems to exist. Not clear there is a lot of evidence it's relevant. If you sequence a tissue that has cancer or some other disease that causes increased cell division, you will see more somatic variation. Not sure why this is particularly surprising or interesting. It's been known for a while now. If somatic variation was important for brain development or function (like it is in the adaptive immune system), that indeed would be super surprising, but that's not what I'm seeing here.

A key aspect of CNS development is massive overproduction of neurons, and then selection for useful ones. The idea that somatic variation plays a role there is not novel.


> It doesn't mean we can't compute with them, nor that the variation is useful or relevant.

This is pretty much my understanding of it as well.

We can expect that, even though we're now at the point of being able to appreciate the minute differences in sequence from cell to cell, almost all changes will have no significant effect on phenotype. However, in aggregate, on the scale of tissues, the could be some interesting effects? But I doubt it.

No meaningful parts (which encodes proteins and gene regulation) are different, however. Nature does not work that way.

Comparison of two genomes as two billions-bases-long strings is meaningless and yields nonsense due to waste and introns. Genome isn't a uniform string in the first place.

Nothing to see here, except hipster's self-praise and want for attention.

I was told in science classes that all of a person's cells shared the same DNA. Now I learn, nobody ever actually tested to see if that was true. This is why people don't trust you, science.

> This is why people don't trust you, science.

Funny... but I wish that were the case.

Last week when I was picking up my kids from school, I challenged another parent to confirm her bumper sticker's claim that the Earth is flat. Sure enough, she told me to my face that yes, the Earth is flat, that I've "been lied to," and that I should "look into it." I'm still reeling from that.

I happen to know that "religion" is at play in this case, not the critical analysis of conflicting information. Likewise, my uncle, who is a lifelong engineer on the space program (via contractors), still believes very zealously in all sorts of superstition. There's apparently a cottage industry of authors who try to reconcile biblical literalism with contemporary science. Alan Kay talks about this somewhere, how even scientists are prone to ridiculous and unsupportable beliefs.

Right now (and maybe forever?) we have a Zeitgeist where "skepticism" appears to be tied to popular tribal identities, including evangelical Christianity. Despite the above, though, I doubt that anti-science sentiments are actually very widespread. I think we're hearing a lot about it because industries (energy in particular) are using people's distrust of authority and institutions to muddy the waters, so to speak, in public narratives where they see the truth as a threat.

As you said, superstitions didn't prevent your uncle from building rockets. I propose to 'allow' personal beliefs and tribal identities and keep science out of the line of fire as much as possible. It's unfortunate when religion influences real world politics, likewise it's unfortunate that atheist preachers use science as a platform and create an us-vs-them mentality.

Also, quite a bit of that half-serious scepticism is actually critical thinking; an experiment in researching topics, finding additional angles to complex issues and expressing dissenting opinions which was not possible before the internet.

So let's say the moon landing was fake, just for fun. Let's look at the fotos, look for clues or contradictions in old publications. Let's say you're ill and in pain, and none of the doctors could help or give relief.

It's easy to see the appeal of finding your own truth, no?

Sure that was not said in an ironic way? Flat earth stickers surely have to be satirical.

> I was told in science classes that all of a person's cells shared the same DNA. Now I learn, nobody ever actually tested to see if that was true.

Actually, we've known that was wrong for a very long time, but also a useful approximation of the truth. Which is why very low level science classes tend to include it.

It's kind of like Newtonian mechanics, which you were probably also taught in science classes, and is also not true.

>useful approximation of the truth

This must be fantastic material for trolling... "What Clapper said in front of Congress was a useful approximation of the truth." You almost got me. Well played.

newtonian mechanics is perfectly true in certain contexts.

>perfectly true

Stricto-sensu it's not true. Newtonian mechanics constitute a model, and all models have error-terms.

As the saying goes, "All models are wrong; some models are useful".

That's not why people don't trust science.

Science has become a pawn in the cultural conflict that seems to go on in America these days; the classic battlefield of "evolution vs. creation" has expanded to a World War 1 - style trench warfare going through all parts of society, with various major battles around things like "vaccination vs. autism" flaring up all the time.

This will doubtless hurt science. While a neutral science can trivially correct old theories when new evidence shows up, ideologically entrenched science can't easily give up ground. Saying two neurons don't share DNA might be harmless as it touches no sensitive spot in society - who cares? But what if multiple vaccinations (i.e. significant stress for the body to fight a disease) for for young kids actually turned out to be problematic in some circumstances? This won't be pretty on social media.

"who cares? But what if multiple vaccinations (i.e. significant stress for the body to fight a disease) for for young kids actually turned out to be problematic in some circumstances?"

This is a trivial argument. The benefits of vaccination is both individual and that a large population of immunised individuals The idea of herd-immunity is a large percentage of the population is immunised the chances of disease spreading is minimised. [0]

Vaccinations are effective because individuals taking vaccinations develop immunity and if they come into contact with antigens again, anti-bodies are produced to fight. This is important for infants, who if exposed to an antigen, the time taken and effectiveness of response is weak. [1]


[0] http://www.nhs.uk/Conditions/vaccinations/Pages/How-vaccines...

[1] https://www.cdc.gov/vaccines/vac-gen/howvpd.htm

Spot on.

Hope you didn't miss my point though. Say you discover data that leads you to suggest a different vaccination procedure. That is difficult to communicate in an ideologically entrenched environment, don't you think?

Look how the parent post expressed discomfort already in the face of harmless new information relating to neurons.

"Say you discover data that leads you to suggest a different vaccination procedure."

There are plenty of examples of how accepted treatment is hard to shake. Take for example ^stomach ulcers^. Barry Marshall conducted self experiments to prove the H. pylori theory. The initial work started in '82. Marshall/Warren won the Nobel prize in 2005 [0] for this work. It changed the way stomach ulcers were understood and the treatment.

[0] https://en.wikipedia.org/wiki/Barry_Marshall

Not trivial if it turns out vaccines are linked to autism.. don't assume everyone is a hard utilitarian

"if it turns out vaccines are linked to autism"

I don't believe you, please show me some peer reviewed science instead of waiving around some ^hokey-pokey^ rubbery belief.


It seems you were making the argument that even if autism was linked to vaccines, the benefit would outweigh the cost. Now you are attacking me on a different point (that I didn't make)

"It is unclear whether decisions people made about vaccination were influenced by their exposure to certain tweets and media, or whether they simply chose to inhabit an online community that reinforced their beliefs, a tension known as contagion versus homophile." [0]

Interesting article on role of social media. Obviously you are a hard core, a non-fence sitter, so I'll ignore you.

[0] http://www.smh.com.au/national/health/how-twitter-more-accur...

We appreciate your many contributions to HN. But you've crossed into incivility in this thread. Would you please not do that, regardless of the other comments?

Vaccines are also a classic flamewar topic that, unless there's something genuinely new to be said, are off-topic here: https://news.ycombinator.com/newsguidelines.html.

"The bottom line is that when you add up all of the genetic risks, it looks like genetics can account for 50 percent of the risk for autism, which is very high,” -- David Amaral, an Autism specialist UC Davis MIND Institute. ~ https://www.vox.com/science-and-health/2017/5/11/15508006/wh...

Yes you're write Dang. Incivility vs factual evidence. Maybe I should be more tactful.

"if it turns out vaccines are linked to autism.."

Facts not superstition, reducibility through empiricism. Rational thought instead emotion. Ideas like this were fought and won during ^the Enlightenment^ some 200 to 250 years ago. [0]

[0] https://en.wikipedia.org/wiki/Age_of_Enlightenment

What do people who dont trust science trust instead? Not the religious nuts who would prefer to pray away an illness than get treatment, but the rest, lol.

Follower of Christ here. The short answer is, you can't trust anything. Science is neutral and good because, if true, you can reproduce and see for yourself. The problem is, you can't trust the reporting. I see science-related reports the same way I see political reports – bias with an incentive to lie.

If I were well-versed enough to read the white papers, I would probably trust it a little more. But even then you can't be certain unless you perform the experiment yourself; it's not uncommon for scientists to leave out inconvenient data to get the result they want.

Such is the state of this world – you can't truly know a fact for a fact unless you actually see it for yourself. And even then there's room for doubt :)

Thats certainly better than trusting just to faith to solve things and understandable. I would say about the same. Its an interesting philosophical problem, what we know, and how we know it. I guess instead of black and white trust or not trust I would rephrase and question peoples distrust of highly likely things.

Ah, but then you get into the trouble of what "highly likely" means :) Outside of common observances, the "truths" that we know are only known because they happened to be spread by society – much like how DNS works.

Here's a thought experiment. The government has assisted in pushing the idea of "eggs are bad for you" for decades. In effect, many people truly believe that "eggs are bad for you" is a fact. If you, being slightly more knowledgable in the subject, tell one of those people that this is a load of bollox, and have a paper to back it up... would you actually convince them? You'd be one voice against many; a rebel against history. If you did managed to convince them, would it be due to raw truth, or due to the effectiveness of your rhetoric?

True, that is a whole rabbit hole in itself, but I think you know what I meant :D. I do subscribe to that line of reasoning myself.

Though most things are at least a little subjective, there is always lets say a confidence value or percentage everyone could apply to some bit of knowledge, and while those may vary significantly across the population, some things could just objectively be said to be more likely than another. I dont think much of anything is 100% true, but 99%? Sure.

Im like, 99.99999% sure that this laptop is real and is about to run out of power, but I could be wrong.

Certainly, I didn't mean to go so far as to say what we can see and touch might not be real. As far as I'm concerned, that's covered in the "common observances" I mentioned in my previous comment.

The "truths" I was referring to are things we can't verify ourselves (due to practicality or lack of knowledge), yet are commonly believed or taken for granted. Some examples:

- World maps

- Authorship (of music, books, etc.)

- Photos (see #bowwowchallenge for a good laugh)

- News

- The immutability of physics :)

First principles. A priori logic. There is a long history of antiempiricists in philosophy.

I minored in philosophy and that has always interested me, though not quite to the extent of anti-empiricism, haha.

If you ever want to chat lmk I come at the world from a pretty anti empiricist angle these days

People don't trust "science" because people are not taught logic , critical thinking and the idea behind the scientific principle. Instead, people do celebrity worship (even of scientists !!!) and follow abrasive personalities.

>People don't trust "science" because people are not taught logic, critical thinking and the idea behind the scientific principle.

Well, science is not the idea of "logic, critical thinking and the scientific principle" -- it's its realization in practice.

And from private interests to careerism and ego, that practice is quite far from the idea.

I think we are saying the same thing.

You say science is the realization of logic and critical thought. I'm saying "people" are uneducated about logic and critical thought and hence will clearly not understand "science".

I don't think you are saying the same thing.

You say "people don't trust science because their education is lacking".

Other guy says "people don't trust science because science is often perverted to promote a specific agenda".

Neither of you is wrong, but if I understand correctly you aren't saying the same thing.

>You say science is the realization of logic and critical thought

The far from perfect, and often illogical and uncritical realization of logic and critical thought.

When I teach biology classes, I emphasize that what I am teaching is an approximation of a much more complicated reality. Simplification is a useful didactic strategy. Students will get more details later if they need them (i.e., in graduate school or reading the original papers).

Unfair. Up until just a few years ago, genome sequencing cost thousands or hundreds of millions of dollars or was impossible. How was anyone going to check? The statement is almost entirely true (a few thousand changes out of 3 billion basepairs), anyway.

>How was anyone going to check? //

... that is why one shouldn't trust the current science establishment, writ large, IMO.

If you ascribe to a falsificationist/Popperian scientific method as most claim to do in the scientific establishment then what you should have been claiming is that "our best theory, as yet unfalsified, is that all cells of the human body have the same DNA". It is in no way contingent on the ability of anyone to check, because scientific statements [within the aforementioned philosophical frameworks] can not be confirmed to be true.

That's as strong as it gets, that's the most that "science" can say; but instead of keeping within the epistemological limits of scientific enquiry scientists want to go further [arguably they long for certainty with a sort of religious fervour], so they say things like "all human cells share the same DNA" and print it in text books, and repeat it year after year to school kids and anyone else listening.

Then, when it turns out that it's wrong that is the point where people don't trust "science", and quite rightly so IMO. The story now is "science was wrong" whilst in fact it was the scientist who refused to keep to the limits of what science can offer with regards to certainty that were wrong.

I think you can argue the pushing of facts to be blindly accepted(!) as a methodology for teaching of science, but I don't find that line of argument compelling; it's also something that most scientists will rail against when done outside of the scientific establishment.

[Sorry, but still smarting from high-school chemistry "well actually all that stuff we told you about atoms being like solar-systems was a huge lie, s- p- d- and f- orbitals is where it's at", only then to be told 2 years later "oh, that was all a huge lie, electrons aren't confined in that way, they don't even orbit".]

>The statement is almost entirely true //

Lol, are you a politician, this is what's also known as "false". The statement that "all of a person's cells [share] the same DNA" (by danjoc) has been demonstrably false for years, _THAT_ is science. I'm surprised to see this sort of defence of anti-scientific thinking from you [you don't know me I just know your work].

The little bits where a statement that appeared a priori to be true yet isn't, they are the interesting bits, they're the bits where scientific curiosity is focussed, they're usually the important bits. "It's nearly right" is anathema to scientific progress.

> Then, when it turns out that it's wrong that is the point where people don't trust "science", and quite rightly so IMO. The story now is "science was wrong" whilst in fact it was the scientist who refused to keep to the limits of what science can offer with regards to certainty that were wrong.

Actually, in most cases it isn't the scientists themselves, it is the PR department, or the journalists that are simply looking for a story

> I'm surprised to see this sort of defence of anti-scientific thinking from you [you don't know me I just know your work].

You obviously don't, as you would then know that I am very comfortable with approximations and continuums of belief. 'All of a person's cells share the same DNA' is far more true than its negation 'all of a person's cells do not share the same DNA'.

If we waited until we were absolutely sure of something we wouldn't be saying much ever would we? Isn't the whole point of science to postulate things and then prove or disprove them? Advances can also take "proven" things and prove them wrong.

>we wouldn't be saying much ever would we? //

We could say plenty within the standard scientific framework of presenting hypotheses, testing, promoting to theory. Indeed if you're a scientist that follows a falsificationist methodology for the progress of scientific understanding then all science - all knowledge, for realists - is within that framework.

>Advances can also take "proven" things and prove them wrong. //

No, because proven means something is true, if it's proven that the claim was wrong then it was not proven in the first place.

In _science_ things are held as theories. If they're not yet falsified, they get stronger the more they're tested and not found lacking. The only "truths" are our assumptions/axioms, claims for scientific truth beyond that are scientism.

>If we waited until we were absolutely sure of something we wouldn't be saying much ever would we?

Parent ask for those things to merely be tested. Not to have absolutely certain conclusions from those tests.

You have gotten enough contra for this as this has nothing to do with science but teaching (and has long been tested), but one misconception I have not seen addressed yet is the fact that although there are some differences between cells, those are minimal from a genome stand point (a few changed letters of 10^9 in total). If you have two books with the same text and one has ten commas more, randomly distributed through the book, you would probably also call them identical(or not even notice) although they are not.

As a further note, while we can sequence the genome of cell bulks since about 2004, sequencing of single cell sequencing came up in the last ten years (with an accuracy of about 99.99%, so many random mistakes add up to a much higher degree of variation as is observed here), so if you did not went to science class less than ten years ago (with a teacher trained in the same time frame), your argument does not really make sense.

Thats not a reflection on science, its a reflection on how complicated the world really is..

We are taught progressively better approximations of the state of the art in school because its impossible to go from 0 to grasping everything in a flash. The state of the art itself changes as science tests old assumptions, which is also limited by the kinds of experiments they can run and tools - like CRISPR is enabling scientists access to precisely mutate genes and run experiments that were not possible before.

Its silly to blame science because all of genetics can't be explained as simply and neatly in 5 minutes as you'd like it to be.

> This is why people don't trust you, science.

And instead they go with anecdotal shit like "holy water", "homeopathy", "christian 'science'", etc. which are even more untested.

Or, in many cases, tested and conclusively demonstrated not to be real.

The entire point of science is that trust is not needed, since you should be able to verify the experiments for yourself.

Also, please don't confuse the conclusion in some paper with the scientific method. Authors apply the scientific method to a subject and produce results (data). What they conclude from these results -- acquired through empirical study -- is entirely subjective (and often wrong). But that's how we learn.

i always wondered how differentiated cells can have completely identical DNA and still know which proteins to fold based on their specialized function. different types of cells even look very different!

I think that a one-word answer would be "epigenetics". Sections of genes are turned on and off by various chemical processes, so that the genes that are actively transcribed into proteins can change without the underlying DNA changing.

There was a brief mention of it at the bottom of the article.

Epigenetics, as has been pointed out. But also just the very basic mechanisms of hormones and other signalling and regulating molecules. DNA is just the code. Cells also keep 'state', mostly through the specific molecules in the cytosol.

I'm no expert but I have heard this explained. You can explain it without needing cells to have different DNA. Differentiated cells express different genes from the same genome.

Ok, but this article does not explain that.

What? People trust science. If they don't they are morons. Of course sometimes things and long held truths are proven wrong or different from new discoveries but that does not at all hurt science, this is the process.

> People trust science.

Very large numbers do not.

> If they don't they are morons.

Perhaps, but that doesn't mean they don't exist.

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