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How much a baby is touched leaves measurable effects on DNA methylation (2017)

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Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#21

Post by mindfulhack »

glofish wrote: post #3

I think there is a high chance that is 100% bullshit. Most likely has to do with confusing cause-and-effect. It could be just as well that highly methylated babies cry more and could be more demanding or parents with highly methylated babies are themselves less tolerant to crying thus end up handling babies more. The problem, they way it is being reported, and they way it lines up with pseudo-scientific mumbo-jumbo g…

I'm not a professional scientist, but shouldn't the spirit of science be curiosity and exploration at all times, not shooting down a new idea as soon as you hear it?

If such an attitude were present in every person, science would not progress at all.

I'm not that long a veteran here, but I think at HN we are more interested in having our minds and ears open and feeling we can comfortably share and discuss articles that make us think, than fostering an attitude like this.

I mean this with respect, whoever you are.

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#22

Post by carbocation »

mindfulhack wrote: post #21
glofish wrote: post #3

I think there is a high chance that is 100% bullshit. Most likely has to do with confusing cause-and-effect. It could be just as well that highly methylated babies cry more and could be more demanding or parents with highly methylated babies are themselves less tolerant to crying thus end up handling babies more. The problem, they way it is being reported, and they way it lines up with pseudo-scientific mumbo-jumbo g…

I'm not a professional scientist, but shouldn't the spirit of science be curiosity and exploration at all times, not shooting down a new idea as soon as you hear it? If such an attitude were present in every person, science would not progress at all. I'm not that long a veteran here, but I think at HN we are more interested in having our minds and ears open and feeling we can comfortably share and discuss articles th…

I think that science works best if we marry two mindsets: the joy of seeing something novel, and the suspicion of seeing something too good to be true. They don’t have to be present in equal measure for every article, and while I wouldn’t word it the same way as the parent, I appreciate the healthy skepticism on this topic.

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#23

Post by tomrod »

anbop wrote: post #17
tomrod wrote: post #12

Earlier quoted context omitted.

It's not vanishingly tiny, simply small. Can you think of a reason selection bias could be an issue, thus invalidating twin study cohorts?

Adoptive parents are people who have gone through a lot of effort and expense to get their children, so they're far more likely to be heavily invested in their kids. It's also expensive so they're likely to have money. If the effects of parenting are strong, but "cap out" -- i.e. above a certain level of care, parenting does little, but before that level it has a strong effect -- then twin studies will show little of…

I'm not sure I follow the causality argument here.

A twin study should normalize everything genetically. Ergo epigenetic expression and environment are the only two causal levers. It sounds like you're arguing that parental involvement has a causal impact, which is the point of the studies to a degree.

Perhaps my original question was unclear: is there something the twins do or have done to them that cause a latent selection bias before adoption, thus invalidating the twin studies approach as a whole?

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#24

Post by telesilla »

baxtr wrote: post #19
dcolkitt wrote: post #6

Earlier quoted context omitted.

One thing that we know from decades of twin studies is that childhood family environment explains a vanishingly small percent of long-run adult outcomes. Contextualizing this single study's result against the much larger, more established evidence from twin studies strongly suggests that one or more of the following is true. - The results are spurious and won't replicate. - The results are true, but the association i…

I don’t know. I have read this before. But this goes so much against my gut feeling and what I have experienced that it is hard to believe. It’s counter intuitive to say the least.

The documentary Three Identical Strangers also agrees with you, a fascinating account of triplets separated at birth to study parenting.

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

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#25

Post by 08-15 »

Even if this result is real (I smell bad statistics), it's completely useless.

All cells in our bodies have the same genome. But a hepatozyte and a neuron are very different cells, aren't they? The difference is that cells specialize, and they do so by selectively methylating their genome (not the only mechanism, but an important one), thereby modifying the expression of genes. So a liver has a very different epigenome than the brain of the same person. Now here we're looking at a study of the saliva epigenome, apparently the most important tissue they could come up with.

Then they don't analyze the epigenome in any interesting way. Generally, the more a cell specializes, the fewer genes are active. Expressing this as "more mature" is rather dumb. "More geriatric" would be equally appropriate. Does it not matter at all, which genes are methylated?

So, let's summarize the study properly:

"If you don't touch your child enough, his saliva with age more slowly."

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#26

Post by glenstein »

mindfulhack wrote: post #21
glofish wrote: post #3

I think there is a high chance that is 100% bullshit. Most likely has to do with confusing cause-and-effect. It could be just as well that highly methylated babies cry more and could be more demanding or parents with highly methylated babies are themselves less tolerant to crying thus end up handling babies more. The problem, they way it is being reported, and they way it lines up with pseudo-scientific mumbo-jumbo g…

I'm not a professional scientist, but shouldn't the spirit of science be curiosity and exploration at all times, not shooting down a new idea as soon as you hear it? If such an attitude were present in every person, science would not progress at all. I'm not that long a veteran here, but I think at HN we are more interested in having our minds and ears open and feeling we can comfortably share and discuss articles th…

That's great for a classroom setting, or in the lab, or wherever people are forming hypothesis. But in articles communicating research, accuracy matters. You can believe in the value of creative thinking and also want article that do a good job describing research.

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#29

Post by [deleted] »

glofish wrote: post #3

I think there is a high chance that is 100% bullshit. Most likely has to do with confusing cause-and-effect. It could be just as well that highly methylated babies cry more and could be more demanding or parents with highly methylated babies are themselves less tolerant to crying thus end up handling babies more. The problem, they way it is being reported, and they way it lines up with pseudo-scientific mumbo-jumbo g…

[deleted]

Re: How much a baby is touched leaves measurable effects on DNA methylation (2017)

#30

Post by MaximumYComb »

dcolkitt wrote: post #20
aidenn0 wrote: post #11

Earlier quoted context omitted.

There are issues with twin studies, not the least of which the number of twins raised separately, but not adopted, is tiny. However adoptive parents are a small self-selected subset of the population.

Most twin studies simply compare identical and fraternal twins in non-adopted households. Since identical twins share twice the genetic covariance of fraternal twins, the impact of family environment can be backed out from the respective intra-pair correlation coefficients. In the limit case if genetics played no factor, then fraternal and identical twins should have identical pairwise correlations. For example suppo…

In case you're interested, IQ is much more heritable than that for adults. The following quote is from Wikipedia:

"Twin studies of adult individuals have found a heritability of IQ between 57% and 73%[6] with the most recent studies showing heritability for IQ as high as 80%[7] and 86%.[8]. IQ goes from being weakly correlated with genetics, for children, to being strongly correlated with genetics for late teens and adults. "

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