> Things get even fuzzier when you throw in heritable epigenetics too.

Heritable epigenetics is a nascent field. We have yet to get any real promising research showing it even occurs to a significant degree in human.

I would assume it's not a significant factor until we can find even some minimal evidence to suggest that it's an influence in humans. Even then, my guess is that the impact would be minimal. I know this is contrary to a lot of the "trauma passed down through epigenetics" narratives that are going around, but the actual science is in a very different place than the popular understanding of the topic.

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tptacek 3 hours ago | parent | next [-]

Whether or not epigenetic effects are passed down, epigenetics almost certainly impacts trait expression and complicates the "innate vs. environmental" narrative of hereditarians. I don't believe "inherited trauma" woo either, but epigenetics is much more fundamental to genetic science than that.

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Aurornis 3 hours ago | parent [-]

Traditional epigenetics is very different than heritable epigenetics.

Epigenetics is most definitely a factor in humans.

Heritable epigenetics is a different story. There is some early evidence suggesting that transgenerational epigenetic effects appear in humans, but it's very early. Some of the first claimed discoveries of transgenerational epigenetic inheritance in humans turned out to be mistakes by researchers. A lot of the theories about human transgenerational epigenetic inheritance revolve around exposure to famines and food crises, which is unfortunately complicated by the way food crises shape dietary behaviors and eating habits which are also passed down via tradition (not genetically).

The difficult part is that journalists often use "epigenetics" to refer to heritable epigenetics, and a lot of commenters make the same mistake.

	▲	tptacek 3 hours ago \| parent [-]
		Right, I'm not pushing back on you, just sticking up for the idea of paying attention to epigenetic factors in this broader question of innateness.

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sudosysgen 3 hours ago | parent | prev [-]

These are twin studies, you don't need to get into heritable epigenitics. The expression of the shared environment in the womb would be reasonably expected to lead to epigenetic correlations in twins at a crucial stage of development where they would have the highest impact, without them being heritable.

Put simply, the common epigenetics between twins need not be held in common with the parents.

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Aurornis 3 hours ago | parent [-]

> The expression of the shared environment in the womb would be reasonably expected to lead to epigenetic correlations in twins at a crucial stage of development where they would have the highest impact, without them being heritable.

Sure, but that wouldn't be relevant to twin studies because both twins would be exposed to the same environment.

The pop culture discussion about heritable epigenetics tends to assume influence outside of in utero conditions or crossing multiple generations. It's where the "generational trauma is in your genes" idea came from.

	▲	tptacek 3 hours ago \| parent \| next [-]
		We're discussing twins raised apart. They're not necessarily in the same environment (except during gestation).
	▲	sudosysgen 3 hours ago \| parent \| prev [-]
		It would be relevant to twin studies. Specifically, separated twin studies, where shared environment is assumed to be negligible. If the developmental impact of epigenetics is significant that won't be true.