4 ms·

Cultural changes rate are too infinitesimal compared to the time which is required for any genetic change to get a chance to form and propagate through a popula

by lngnmn 10y ago

Cultural changes rate are too infinitesimal compared to the time which is required for any genetic change to get a chance to form and propagate through a population to attain a stable presence (forming a distinct trait). The probability that a certain cultural difference induced mutation could be formed (given that there is no flow of information from a phenotype back to genotype) is something incalculable. What might work for a bacteria does not work for humans due to, you see, fundamental differences in the reproductive system and development. There are a few main principles from genetics 101 to consider before making any attempts of "doing science". 1. all mutations are *random* 2. there is no backward flow of information 3. environment does not alter DNA. random mutations do 4. propagating of a mutation is an extremely rare event 5. it takes *many* generations. To understand these principles think why we do not have much mutations of, say, hemoglobin or glucose pathway enzimes. There is another fundamental principle: way to many hipsters in what they call "modern science".

danharaj 10y ago
The article talks about gene expression, which is much more fluid. Another factor that influences gene expression whose effects are just starting to be measured is poverty.
- lngnmn 10y ago
  Gene expression has nothing to do with altering DNA, leave alone any propagation of such "changes".
  - danharaj 10y ago
    > The study examined DNA methylation—an “annotation” of DNA that alters gene expression without changing the genomic sequence itself—in a group of diverse Latino children. Methylation is one type of “epigenetic mark” that previous research has shown can be either inherited or altered by life experience. What are you even arguing against?
    - lngnmn 10y ago
      I am arguing against ignoring the fundamental principle about one-way flow of information DNA->RNA->protein which makes life sustainable. Anything which contradicts with this principle is plainly nonsense - a product of unconstrained imagination. BTW, any changes which could be propagated through the mother's body, the way some deceases do, would not get into the DNA. This is another fundamental principle which contributes to sustainability of life - it is about isolation and washing out of pathogens.
      - maxerickson 10y ago
        Are you rejecting epigenetics entirely then?
      - toufka 10y ago
        See my comment above. DNA can be commented in/out during an organism's lifetime. And these comments/silencing capabilities are in fact transferable to a child with some fidelity. And in that way those changes are heritable and genetic, if not actually altering the DNA of the child in any way. This capability is called epigenetics. You are correct that the code of the DNA itself is not being altered, but there are other heritable mechanisms that affect the structure, capability and accessability of that DNA - i.e. gene expression, beyond the code of DNA itself. This enables capabilities encoded in DNA to be passed down to children without actually using them - or conversely, to enable certain latent capabilities under certain environmental conditions. Life is a bit more nuanced than the dogmatic one-way flow of information we teach as 'the central dogma'. It gains its complexity by always having an exception to its own rules somewhere at some point if it physically possible so, as to hedge against some change in conditions where that exception becomes more powerful than the existing rule. The exception may be inconsequential and of little benefit - until such time as it is not.
        lngnmn 10y ago
        With generational time of almost 20 years? What you are taking about is an ordinary blood-borne sexually transmitted decease model (or a virus), and it has nothing to do with genetics (gene expression is a developmental topic), so there will be no "marks on a DNA" in principle - it does not work that way. There, however, could be some certain proteins bound to DNA, but it is a not a genetic but biochemical (pathogenic-like) change. Those proteins could be treated as markers. The propagation rate of such proteins is still limited by the generation time, so any connection to cultural differences is nonsense. So, it is not genetic, there is no marks on DNA, it is not cultural. Period.
maxerickson 10y ago
A cultural environment could induce a nearly instantaneous change in the genetics of a population though. Say some percentage of a population has tails. Then they start getting killed because they have a tail. A generation or two later, a much smaller percentage of the population will have tails. The likelihood of tails appearing in the population has decreased dramatically, due to culture.
- lngnmn 10y ago
  > instantaneous change in the genetics of a population though. How exactly, given that a generational time for humans is about 20 years?
  - maxerickson 10y ago
    Say 5 people out of 25 have tails at time=0. One day, the 20 without tails kill the 5 with tails. So at time=0, the prevalence of tails is 20%. At time=1 day the prevalence of tails is 0%. The remaining members of the population may still have the genes to make a tail, but no one currently has a tail. If tails are a dominant trait, they won't. If tails are a recessive trait, a couple generations of killing babies with tails will do quite a lot to further diminish the prevalence of the trait.
    - lngnmn 10y ago
      Do you understand the fundamental difference between a simulation according to some primitive model and reality?
      - maxerickson 10y ago
        Probably not. I used a cartoonish model to starkly illustrate the possibility of the effect. That doesn't mean I think reality would have such stark effects. It doesn't mean I think I've proved the effect occurs in reality.
macawfish 10y ago
As is common with popular education, the "101" classes tend to propagate outdated information and ideas. For some reason they think they need to teach things in historical order. https://www.gesundheitsindustrie-bw.de/en/article/dossier/epigenetics-heritable-traits-without-changing-the-dna-sequence/ https://www.gesundheitsindustrie-bw.de/en/article/dossier/ep...

by lngnmn 10y ago

danharaj 10y ago

The article talks about gene expression, which is much more fluid. Another factor that influences gene expression whose effects are just starting to be measured is poverty.

lngnmn 10y ago
Gene expression has nothing to do with altering DNA, leave alone any propagation of such "changes".
- danharaj 10y ago
  > The study examined DNA methylation—an “annotation” of DNA that alters gene expression without changing the genomic sequence itself—in a group of diverse Latino children. Methylation is one type of “epigenetic mark” that previous research has shown can be either inherited or altered by life experience. What are you even arguing against?
  - lngnmn 10y ago
    I am arguing against ignoring the fundamental principle about one-way flow of information DNA->RNA->protein which makes life sustainable. Anything which contradicts with this principle is plainly nonsense - a product of unconstrained imagination. BTW, any changes which could be propagated through the mother's body, the way some deceases do, would not get into the DNA. This is another fundamental principle which contributes to sustainability of life - it is about isolation and washing out of pathogens.
    - maxerickson 10y ago
      Are you rejecting epigenetics entirely then?
    - toufka 10y ago
      See my comment above. DNA can be commented in/out during an organism's lifetime. And these comments/silencing capabilities are in fact transferable to a child with some fidelity. And in that way those changes are heritable and genetic, if not actually altering the DNA of the child in any way. This capability is called epigenetics. You are correct that the code of the DNA itself is not being altered, but there are other heritable mechanisms that affect the structure, capability and accessability of that DNA - i.e. gene expression, beyond the code of DNA itself. This enables capabilities encoded in DNA to be passed down to children without actually using them - or conversely, to enable certain latent capabilities under certain environmental conditions. Life is a bit more nuanced than the dogmatic one-way flow of information we teach as 'the central dogma'. It gains its complexity by always having an exception to its own rules somewhere at some point if it physically possible so, as to hedge against some change in conditions where that exception becomes more powerful than the existing rule. The exception may be inconsequential and of little benefit - until such time as it is not.
      - lngnmn 10y ago
        With generational time of almost 20 years? What you are taking about is an ordinary blood-borne sexually transmitted decease model (or a virus), and it has nothing to do with genetics (gene expression is a developmental topic), so there will be no "marks on a DNA" in principle - it does not work that way. There, however, could be some certain proteins bound to DNA, but it is a not a genetic but biochemical (pathogenic-like) change. Those proteins could be treated as markers. The propagation rate of such proteins is still limited by the generation time, so any connection to cultural differences is nonsense. So, it is not genetic, there is no marks on DNA, it is not cultural. Period.

maxerickson 10y ago

A cultural environment could induce a nearly instantaneous change in the genetics of a population though. Say some percentage of a population has tails. Then they start getting killed because they have a tail. A generation or two later, a much smaller percentage of the population will have tails. The likelihood of tails appearing in the population has decreased dramatically, due to culture.

lngnmn 10y ago
> instantaneous change in the genetics of a population though. How exactly, given that a generational time for humans is about 20 years?
- maxerickson 10y ago
  Say 5 people out of 25 have tails at time=0. One day, the 20 without tails kill the 5 with tails. So at time=0, the prevalence of tails is 20%. At time=1 day the prevalence of tails is 0%. The remaining members of the population may still have the genes to make a tail, but no one currently has a tail. If tails are a dominant trait, they won't. If tails are a recessive trait, a couple generations of killing babies with tails will do quite a lot to further diminish the prevalence of the trait.
  - lngnmn 10y ago
    Do you understand the fundamental difference between a simulation according to some primitive model and reality?
    - maxerickson 10y ago
      Probably not. I used a cartoonish model to starkly illustrate the possibility of the effect. That doesn't mean I think reality would have such stark effects. It doesn't mean I think I've proved the effect occurs in reality.

macawfish 10y ago

As is common with popular education, the "101" classes tend to propagate outdated information and ideas. For some reason they think they need to teach things in historical order. https://www.gesundheitsindustrie-bw.de/en/article/dossier/epigenetics-heritable-traits-without-changing-the-dna-sequence/ https://www.gesundheitsindustrie-bw.de/en/article/dossier/ep...