I and others generally don't quote things that aren't relevant to the point we're making and I'm not keen on the crypt-accusation. I didn't say that there aren't downstream molecular effects--clearly there are. Rather, the article is very unclear about the nature of epigenetics, and the wording about "transmitting traits" is misleading at best and leads to many unwarranted conclusions, as evidenced in the comments here. The statements I quoted are not about transmitting traits. e.g., "paternal exercise" refers to a trait of exercising, taking time to exercise, being motivated to exercise, etc. The "conferred benefit" of "enhanced endurance and metabolic health" is a different trait. If that is the trait being transmitted then that should be the trait being identified in male parents, not "exercise". Similarly, being exposed to nicotine is not the trait of having livers that are good at "disarming" nicotine, cocaine, and a host of other toxins ... and this is an extraordinary claim that requires extraordinary evidence, and the article provides one citation, from 2017.
And as an epigeneticist says in the article, we have no idea how RNA is having the effects its having.
As I said, I'm happy to wait until we have moved beyond this early stage of research before making any radical inferences.
In the “paternal exercise” case the trait isn’t the habit of exercising, it’s the metabolic changes of exercise that are (apparently) conferred to both father and offspring.
You're completely missing the point that I explicitly stated. The trait that is purportedly being transmitted is metabolic changes that confer some advantage, but that's not what's being measured in the father, "exercise" is--not a word was said about fathers having better metabolic health, just that they "exercise". Which is reason to be skeptical of the claim.
Have you considered that checking for that specifically might not be actually needed? After all, the correlation between exercise and metabolic health is well established.
That was my original thought, however if you want to quantify an effect it would be ideal to measure the same trait in both parent and offspring. I assume that the reason that this was done (I didn’t read the papers) is because this is a retrospective study, where the participants self-report on the exercise level of their fathers, rather than a longitudinal study which could measure the fathers’ metabolic state fitness at time of conception.
Thus, although there is a plausible link, I now agree with the parent post that this is sufficient reason to take the study with a grain of salt (given well known academic incentives to produce positive results, etc).
And as an epigeneticist says in the article, we have no idea how RNA is having the effects its having.
As I said, I'm happy to wait until we have moved beyond this early stage of research before making any radical inferences.