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Cultural differences may leave their mark on DNA

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Re: Cultural differences may leave their mark on DNA

#51

Post by lngnmn »

danharaj wrote: post #45
lngnmn wrote: post #30

Earlier quoted context omitted.

Gene expression has nothing to do with altering DNA, leave alone any propagation of such "changes".

> 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?

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.

Re: Cultural differences may leave their mark on DNA

#52

Post by toufka »

I'll quote myself from a previous comment regarding epigenetics.

Epigenetics. It's the make-file for your genetic source code. Certain conditions can cause certain parts of your genetic code to be uncommented or commented-out. There are actually a number of different kinds of comments (histone modifications [1]) - each set of marks particular to a different compiler, in different contexts. And these comments/marks are copied with some fidelity to daughter-cells/children along with a high-fidelty copy of the underlying genetic code itself.

So the genes themselves are not being heritably altered, rather the recipe for which gene is where, when can be subtly changed. But again, the same mechanisms that permit the change in expression of those genes during a lifetime can be subsequently changed in the next just as easily.

In this way you can store the code for some trait or capability over many generations without having it always be running. It can manifest itself in individual organisms as having very different phenotypes even with the same underlying code.

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

Re: Cultural differences may leave their mark on DNA

#53

Post by maxerickson »

lngnmn wrote: post #43
maxerickson wrote: post #35

Earlier quoted context omitted.

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 wit…

Do you understand the fundamental difference between a simulation according to some primitive model and reality?

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.

Re: Cultural differences may leave their mark on DNA

#54

Post by maxerickson »

lngnmn wrote: post #51
danharaj wrote: post #45

Earlier quoted context omitted.

> 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?

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 contr…

Are you rejecting epigenetics entirely then?

Re: Cultural differences may leave their mark on DNA

#55

Post by toufka »

lngnmn wrote: post #51
danharaj wrote: post #45

Earlier quoted context omitted.

> 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?

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 contr…

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.

Re: Cultural differences may leave their mark on DNA

#56

Post by mcjon77 »

One thing that I don't hear talked about in many of these discussions about the genetic components of race is how the mixed racial ancestry of many "black" people in Europe and the Americas impacts these studies.

MANY blacks in the Americas and Europe have significant European DNA. For example, even though my family identifies as black, my mother and her siblings are almost 50℅ European according to DNA tests.

How does this factor in when making medical decisions based on assumptions regarding race?

Re: Cultural differences may leave their mark on DNA

#57

Post by openasocket »

fvdessen wrote: post #49
svachalek wrote: post #31

Earlier quoted context omitted.

What I understand of the issue is that genetic differences between populations are real, but they form a continuum whose boundaries are extremely blurry if visible at all from a genetic level. Thus the drawing of boundary lines and the assignment of individuals into those handful of categories is something subject to change from culture to culture. In other words, genetic differences do not make race a "biological re…

If you do a clustering analysis on a large sample of DNA data you will get different clusters corresponding to the usual definitions of races or ethnicities, depending on the number of clusters you choose. https://en.wikipedia.org/wiki/Human_genetic_clustering

That wiki page has a pretty substantial "Criticism" section. The Rosenberg et. al. paper even says their paper "should not be taken as evidence of our support of any particular concept of biological race." Their study shows that genetic distance is roughly linear with physical distance, barring obstacles like mountains and oceans. The consensus in the field, based on citations on that wiki page, seems to be that human diversity is a continuum, so any dividing lines you try to make to partition it will be largely arbitrary. It's like looking at a rainbow at trying to divide up the yellow from the orange from the red and so on: you can do that, but your color categories don't completely capture the spectrum visible.

Re: Cultural differences may leave their mark on DNA

#58

Post by LordKano »

mcjon77 wrote: post #56

One thing that I don't hear talked about in many of these discussions about the genetic components of race is how the mixed racial ancestry of many "black" people in Europe and the Americas impacts these studies. MANY blacks in the Americas and Europe have significant European DNA. For example, even though my family identifies as black, my mother and her siblings are almost 50℅ European according to DNA tests. How do…

As I remember it, something like 80% of people who we identify as African Americans(or black) have significant amounts of European ancestry.

Outside of Africa, that's probably to be expected.

I too am "black", with two "black" parents but my mother had red hair and green eyes. My son has blonde hair and blue eyes.

Re: Cultural differences may leave their mark on DNA

#59

Post by marxidad »

toufka wrote: post #52

I'll quote myself from a previous comment regarding epigenetics. Epigenetics. It's the make-file for your genetic source code. Certain conditions can cause certain parts of your genetic code to be uncommented or commented-out. There are actually a number of different kinds of comments (histone modifications [1]) - each set of marks particular to a different compiler, in different contexts. And these comments/marks ar…

What muscles do you have to flex that will eventually lead to methylation of histones?

Re: Cultural differences may leave their mark on DNA

#60

Post by cb18 »

danharaj wrote: post #33
ChemicalWarfare wrote: post #19

Earlier quoted context omitted.

"Race" has 2 meanings. 1. Race as a social construct. It does exist in that capacity - as an extreme example Irish were not considered "white" in America (google for some "hilarious" images from "back in the day"). 2. Race as a biological reality. This is a touchy subject for a variety of reasons. But that doesn't mean that well documented taxonomic differences between human races are "fake". They do exist and are mo…

What does it mean for "race" to be a "biological reality"? Interpopulation diversity of both phenotype and genotype isn't remarkably different from intrapopulation diversity. There are no genetic markers that taken together say "this person is black" or "this person is white". The concept of race was never grounded in real science and its proponents constantly change their justifications after the fact. At one point…

There are no genetic markers that taken together say "this person is black" or "this person is white".

Actually, there very much are.

I think what you're trying to say is that not all black people have all the "black people genetic markers," and likewise for other groups. This is true, but this is not necessary to distinguish well-defined groups.

Family resemblance is a philosophical idea made popular by Ludwig Wittgenstein

It argues that things which could be thought to be connected by one essential common feature may in fact be connected by a series of overlapping similarities, where no one feature is common to all.

https://en.wikipedia.org/wiki/Family_resemblance

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