
Have We Drawn the Wrong Lessons from Epigenetics? - mr_tyzic
http://aeon.co/magazine/science/have-we-drawn-the-wrong-lessons-from-epigenetics
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azakai
> Our new awareness of epigenetics challenges genetic determinism and throws a
> new wrench into nature-nurture debates.

It does?

> Epigenetic studies show that genes alone do not determine form and function,

Of course genes alone do not do that - that's the whole _point_ of the nature-
nurture debate, and the fact that most things are a mix of nature and nurture.
We already knew a long time ago that genes alone do not determine form and
function.

> but that the cellular environment matters in making people who they are as
> biological and social beings.

That also isn't new. Of course the cellular environment matters in making
people (for example, fetal alcohol syndrome is a clear example of that, way
before epigenetics).

The fascinating thing about epigenetics is something else entirely. It is that
there is _inheritance of traits_ via a path that is not DNA. This is
incredibly important and interesting, but was not what showed us that genes do
not determine everything about organisms, we knew that long before. In other
words, we already knew non-genetic factors determined how organisms are formed
and behave, but epigenetics showed us that those non-genetic factors can be
_inherited_.

~~~
RockyMcNuts
hmmh... is that why Dutch people are tall? it's not because short people are
selected out? If you gave a new generation of Dutch the diet/environment from
50 years ago would they revert to the height from 50 years ago? if not, why
not? dumb questions no doubt but I don't really get how "inheritance by a path
other than DNA" actually works, where the additional information gets stored.

~~~
TeMPOraL
DNA is data. A blueprint. But new organisms aren't made in a factory, they're
made by other organisms, which were made by other organisms, etc. So when
environmental factors affect which parts of the blueprint are used in
construction of descendant organisms (and we know they can), those organisms
can be different even though they share the same blueprint. Think of it as
data implicit in code execution state, as children literally fork off the
parent process and continue their lives.

~~~
RockyMcNuts
Makes sense...what I don't really get is how that means 'heritability' other
than through DNA.

Seems to me DNA is kind of like a recipe for beer, and on a humid day the beer
comes out a little different with the same recipe. But if you go back to the
original weather the beer will come out the same.

So if you sent a Dutch couple of today back in time to the diet and
environment of 50 years ago, their kids would be the height Dutchmen would
have been 50 years ago, since the DNA and environment are the same. Nothing
else changed inside the Dutch that would make their kids taller, and the
change in height isn't something that is 'heritable' through other than DNA.

~~~
im3w1l
Methylation of cythosines decrease transcription rate. Meaning a gene becomes
less active. Methylation state is heritable.

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reasonattlm
The article's core point is a misunderstanding of the science and essentially
disproved by the fact that you can use epigenetic decorations to fairly
accurately measure age [1]. A lot of epigenetics is common reactions to common
circumstances, to the point at which the patterns are very similar between
people. Sure everyone's a special snowflake, just like every lawnmower rusts
in a different way, but we also all age due to exactly the same underlying
mechanisms, our metabolisms all operate on the same set of mechanisms, and so
forth. Personalized medicine via epigenetics is the sort of thing you focus on
when you can't outright cure a medical condition by completely repairing the
damage that causes it. It is a consequence of inability to intervene
comprehensively, to the point at which the research community scrabbles for
any handhold that says something about the condition's progression, looking
for comparison points that are mostly similar but just a little different to
try to learn what is really going on. But it isn't the path to the next
generation of medicine, for all that it is the path to getting your grant
funded today.

[1]: [http://newsroom.ucla.edu/releases/ucla-scientist-uncovers-
bi...](http://newsroom.ucla.edu/releases/ucla-scientist-uncovers-
biological-248950)

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tjradcliffe
There is no "lesson from epigenetics", and while I'm somewhat sympathetic to
the author's politics I'm not about to try to claim they in any way follow
from claims that "epigenetic diversity is fundamentally different from genetic
diversity or simple plain old phenotypic diversity."

Not everyone is the same height. We've learned over the past century that
doing our best to accommodate diversity results in a more interesting, happy
and loving world. The source of diversity doesn't matter. We've also learned
that giving people the freedom to make their own choices about their own
bodies is generally better than giving that power to someone who has less
information, like a legislator or a judge.

None of this has anything to do from epigenetics, and there is simply no
political lesson to be had from it, any more than there was a political lesson
to be had from Darwin, despite claims to the contrary by everyone from Spencer
to Marx.

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lbhnact
Being friendly with a few full-time computational and bench geneticists, I can
tell you that none of them say things like "Epigentics has shown us that..."
with great confidence, much less make sweeping claims about multi-generational
heritable traits and clear cut environmental determinants.

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firethief
Good grief.

> Indeed, most of the illnesses and conditions that are the focus of
> epigenetic research, except for cancer, are contested conditions. One reason
> they are contested is that many of them have come into being through
> measurements and statistics that effectively define illness as a deviation
> from a norm rather than as an underlying pathology. Just as type II diabetes
> is now defined by elevated blood-glucose levels (rather than a set of
> symptoms), the Body Mass Index (BMI) clinically diagnoses obesity as a
> larger than average (or what used to be average) weight-to-height ratio. It
> does not actually measure adiposity; in fact, a high BMI can be the result
> of large amounts of bone or muscle as easily as fat. Meanwhile, IQ has long
> been under attack as a culturally biased and non-objective way to measure
> intelligence.

Type II diabetes: does the author not believe a disease can be present before
noticeable symptoms?

Obesity: the shortfalls of BMI are well-known; I doubt there are a lot of
doctors out there who see an athlete with a high BMI and think, "time to burn
some of that muscle"

Brain damage: the author is attacking their own choice of metric for the
condition, in order to... deny the condition's existence??

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gone35
Oh wow, this is one of the few instances where I really _wish_ one could
downvote submissions. What a whole bunch of blatant misinformation and
misrepresentation of the literature. The authors are clearly non-specialists
_and it shows_...

If this is not academic malpractice, I don't know what it is.

