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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 pe

• markcerqueira 9y ago
  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.
  • coldtea 9y ago
    >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.
  • pbhjpbhj 9y ago
    >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.
• leeoniya 9y ago
  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!
  • marcosdumay 9y ago
    Ok, but this article does not explain that.
  • charlieflowers 9y ago
    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.
  • khedoros1 9y ago
    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.
  • roywiggins 9y ago
    Differentiation. https://en.wikipedia.org/wiki/Cellular_differentiation https://en.wikipedia.org/wiki/Cellular_differentiation
  • matt4077 9y ago
    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.
• fao_ 9y ago
  > 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.
  • dragonwriter 9y ago
    Or, in many cases, tested and conclusively demonstrated not to be real.
• biomcgary 9y ago
  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).
• snackai 9y ago
  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.
  • dragonwriter 9y ago
    > 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.
• gavinpc 9y ago
  > 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.
  • UweSchmidt 9y ago
    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?
  • ralfd 9y ago
    Sure that was not said in an ironic way? Flat earth stickers surely have to be satirical.
• vowelless 9y ago
  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.
  • coldtea 9y ago
    >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.
    • vowelless 9y ago
      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".
      • beagle3 9y ago
        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.
      • coldtea 9y ago
        >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.
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• dragonwriter 9y ago
  > 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.
  • nikofeyn 9y ago
    newtonian mechanics is perfectly true in certain contexts.
    • omginternets 9y ago
      >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".
  • danjoc 9y ago
    >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.
• UweSchmidt 9y ago
  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.
  • joshjje 9y ago
    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.
    • simplify 9y ago
      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 :)
      • joshjje 9y ago
        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.
• gwern 9y ago
  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.
  • pbhjpbhj 9y ago
    >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.
• runeks 9y ago
  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.
• patall 9y ago
  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.
• zaptheimpaler 9y ago
  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.