
Babies who get more cuddles have their genetics changed for years, study shows - ALee
http://www.sciencealert.com/cuddling-babies-alters-their-genetics-dna-for-years
======
nabla9
I'm confused by this article.

I have understood that epigenetics refers to heritable changes in gene
function without changes in the genome. Change in gene expression even if it
last the rest of the life of an individual not epigenetic change. But even
university press release says otherwise.

What I'm missing?

~~~
patall
You are missing nothing, its just that modern molecular biology has somewhat
changed in what it regards as epigentics. Now, we usually refer to any
somewhat lasting changes (a few cell cycles, sometimes just for a cell phase)
to DNA as epigentic. This change in meaning has happend (as far as I
understand it) because some of the somewhat traditional epigentic marks (like
DNA methylation) have been found to play an even bigger role in relatively
short time processes. Now almost all base modifications of DNA (and the bound
nucleosomes) are regarded as epigenetic (in the sense of temporal genetic
changes) even though the appearing changes are not really short term
inheritance reasoned anymore but mere functional changes.

And now, the whole story is becoming even more confusing because those base
modifications also happend in RNA (transcribed DNA) which lead to the term
epitranscriptomics, which to be honstest, has nothing to do anymore with
inheritance, it is just about how a RNA molecule interacts with other cell
processes.

------
gwern
Bzzt. Nope. Epigenetics is heritable as are child-rearing practices and this
is a cross-sectional design, not longitudinal. (Not even within-family
comparisons!) For all they know, those epigenetic differences were present
from birth, as is often the case. Yet another epigenetics study whose
overhyped causal claims are dead on arrival.

~~~
SubiculumCode
While you raise valid limitations of the study, those limitations do not
provide a valid cuse to dismiss the result outright. Random assignment to
different levels of "cuddles" in humans is probably not ethical,and
longitudinal studies are expensive. To get a grant funding a longitudinal
study you usually have to have a) animal model based evidence from the
literature b)have already demonstrated in humans the phenomenon cross-
sectionally. As a side note, your comment would have been perfectly reasonable
sounding if you had left off the first two words, and the last sentence. But
you didn't.

~~~
gwern
None of that is true. We have a long history of epigenetics studies which let
us known this is almost certainly yet another failure. Random assignment is
not unethical under many designs (exercise for the reader: think of one. Hint:
draw inspiration from economics), is not necessary to improve over what they
did, and longitudinal designs at their simplest merely require two sampling
periods. It is also untrue that you 'usually' have to have demonstrated it in
animals or cross-sectionally because many longitudinal studies are convenience
samples, record-based or population registries, or collect large numbers of
measurements to see what comes out in later analyses of things they hadn't
thought of before.

~~~
SubiculumCode
Clearly I was not claiming that random assignment is un ethical generally, but
specifically in the case of assigning the degree of physical
affection/cuddling to a baby is probably unethical.

As someone who has been involved in multiple longitudinal studies, although
not in epigenetics, I can say that they are more expensive.

In terms of what I said about prior evidence, I was coming from a cognitive
psych background where we do not typically deal with record-based data. We
deal with participants directly. It is expensive and time consuming.
Longitudinal studies usually follow cross-sectional evidence.

------
woodpanel
A layman's question:

If DNA methylation happens while cuddling, would this always be a good thing
for the baby (e.g. one of the parents has a genetic disease)?

~~~
sxv
If by "good" you mean improved genetic fitness (likelihood of reproduction),
then there is not going to be enough data to support such a claim, since this
would require tracking and comparing the reproductive outcomes of hundreds of
individuals both cuddled and not.

------
louithethrid
Pouring your life into your career cripples ones offspring via epigenetics-
there is a story, that should meet violent resistance on HN.

------
ThomPete
"Gaps between epigenetic age and chronological age have been linked to health
problems in the past, but again it's too soon to draw those kind of
conclusions: the scientists readily admit they don't yet know how this will
affect the kids later in life."

And this is the crux of the matter.

I don't doubt that children who are being cuddles more could have their
genetics changed. Whether it actually has an effect on their prospects later
in life I highly doubt.

~~~
dgut
> I don't doubt that children who are being cuddles more could have their
> genetics changed.

Looks like actual experts in the field disagree with you. [1]

Also, deny a child affection and you have a mentally ill adult. Sadly, there
is now an entire generation of parents who have been advertised things like
the "cry-out" method. [2]

[1] [http://developingchild.harvard.edu/wp-
content/uploads/2010/0...](http://developingchild.harvard.edu/wp-
content/uploads/2010/05/Early-Experiences-Can-Alter-Gene-Expression-and-
Affect-Long-Term-Development.pdf)

[2]
[https://www.goodreads.com/book/show/192222.Solve_Your_Child_...](https://www.goodreads.com/book/show/192222.Solve_Your_Child_s_Sleep_Problems)

~~~
ThomPete
France has done the cry out method for generations.

~~~
dgut
Just because someone has done something for generations doesn't make it right.
They also send children to kindergarten by the 3rd month, for economic
reasons.

Having traveled a bit in Northern Africa, I noticed baby sleep problems are
virtually non-existent there. They do what humans have done for eons: co-
sleeping and breastfeeding. They do it so naturally, mothers are never fully
awake while they breastfeed during the night (wife had to sleep in a room full
of women and children on several occasions).

Biologically, this makes a lot more sense than giving the signal to the most
immaturely born placental mammal that she can't rely on the mother's care.

~~~
ThomPete
Wait are we talking morals or are we talking genetic and statistics?

Denmark sends their kids to nursery school early too and because many women
work full time there it means most children aren't with their parent's for a
long duration of the day (used ot be much earlier).

What you think about it morally isn't interesting to me. Unless you can prove
it's somehow making them worse of then my original position is intact.

~~~
dgut
I think you might have misinterpreted my comment as an argument about moral.

Leaving babies to cry or separating them from their mothers for extended
periods of time is primarily a health issue which I believe should concern
society. [1][2][3] Unfortunately, it fits our economic model very well -- so
there is that.

[1]
[http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.432...](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.432.5090&rep=rep1&type=pdf)

[2] [https://www.cambridge.org/core/journals/development-and-
psyc...](https://www.cambridge.org/core/journals/development-and-
psychopathology/article/role-of-early-experience-in-shaping-behavioral-and-
brain-development-and-its-implications-for-social-
policy/B7D22C728385CFEEEF9675EAC2760054)

[3]
[http://champagnelab.psych.columbia.edu/docs/champ11.pdf](http://champagnelab.psych.columbia.edu/docs/champ11.pdf)

~~~
ThomPete
No, I asked you what we were discussing because it sounded like you were
talking about right or wrong.

If you want it to concern society perhaps first you need to make clear what it
is you are trying to avoid.

I don't see any evidence which proves some larger societal problem.

------
Jumziey
94... Of course you'll find something interesting

(I literally only read the first two sentences)

------
JustSomeNobody
Whether it does or not, cuddle your children.

~~~
draugadrotten
Wouldn't be surprised if it changes the genetics of the cuddling parents too,
it's just that the researchers didn't think of it yet. All those hormones that
are released are going to have an impact.

