DNA carries traces of past events

June 14, 2015 1:19 PM

DNA carries traces of past events meaning poor lifestyle can affect future generations Between week two and week nine of an embryo’s development the genetic code is being rewritten to erase genetic alterations from the parents. However the researchers found that the processes does not clear all of the changes. Around 5 per cent of DNA appears resistant to reprogramming.
posted by Michele in California (23 comments total)

Not clear if this is genetic or epigenetic. I suspect it's epigenetic, which makes this nothing particularly new (obesity, diabetes, trauma and cancer from toxin exposures have all been shown to have epigenetic components).
posted by Punkey at 1:41 PM on June 14, 2015 [8 favorites]

Supposedly, the "news" here is that it applies to what individuals do, not just large scale famine events and the like, and the mechanism for how that happens has seemingly been isolated.

TBH, I hesitated on whether or not to submit it since it doesn't seem like "news" to me either. I have a genetic disorder and thus kind of read a lot about genetics, so I wasn't sure how newsy it might seem to other people. But I thought it was written in an approachable manner, which I always appreciate, since I am a lay person in spite of my familiarity with the subject and that seems somewhat hard to find in genetics articles. So I figured I would hit "post" and leave it up to other people to decide how much value it had to them and I halfway expected to be inundated with "PREVIOUSLY" links.
posted by Michele in California at 1:49 PM on June 14, 2015 [1 favorite]

I believe that tinny sound I hear is the ghost of Trofim Lysenko cackling maniacally.
posted by Bringer Tom at 1:56 PM on June 14, 2015 [30 favorites]

That's how epigenetic changes work - by modifying the molecules attached to the DNA and the proteins it's wrapped around, you can change what genes get expressed and how much. It's not editing the DNA itself, but regulating gene expression. And it works on the individual level, down to individual cells - epigenetics are how a skin cell knows to be a skin cell instead of a neuron. It is also heritable, so the choices and experiences of the parents can be passed down through epigenetics (there was a post here a while back about rats supposedly inheriting a smell-based fear response epigenetically that I can't get because I'm on my phone). We've seen that it plays a huge role in the regulation and function of the brain and hormones, and even have some cancer drugs that work on the epigenetic changes in the cancer cells (HDAC inhibitors). It's really cool stuff.
posted by Punkey at 1:58 PM on June 14, 2015 [7 favorites]

It's hard to know exactly what the "news" is since this article doesn't link to the original paper, "A Unique Gene Regulatory Network Resets the Human Germline Epigenome for Development".
posted by grouse at 1:58 PM on June 14, 2015 [10 favorites]

Ooh, so they found the pathway that covers epigenetic inheritance. That is cool. I'll have to read it when I get home.
posted by Punkey at 2:00 PM on June 14, 2015 [3 favorites]

I kind of thought the original article was probably this: Forget the Parents: Epigenetic Reprogramming in Human Germ Cells and I didn't link to it because I didn't readily see a means to get the full article for free and all that.
posted by Michele in California at 2:03 PM on June 14, 2015 [1 favorite]

There are two other related articles in the same issue of Cell:

The Transcriptome and DNA Methylome Landscapes of Human Primordial Germ Cells

DNA Demethylation Dynamics in the Human Prenatal Germline

My understanding is that the phenomenon of inherited epigenetic alterations has been well-established, but that the mechanisms underlying the phenomenon remain poorly understood. Looks like a pretty interesting set of papers for research geneticists.
posted by kisch mokusch at 2:05 PM on June 14, 2015 [1 favorite]

Epigenetics, previously (tag)
posted by filthy light thief at 2:06 PM on June 14, 2015 [3 favorites]

Fuckin' science journalists not even linking to the paper, fuck.

But beaten to the link by grouse. Fulltext is open access.

So the paper isn't even particularly about what the article says it is, that epigenetics were heritable was already known, but they worked on the mechanism and found some interesting relevant loci for illness etc.
posted by save alive nothing that breatheth at 2:06 PM on June 14, 2015 [1 favorite]

The University of Cambridge's press release ("Reprogramming of DNA observed in human germ cells for first time") doesn't do a bad job of explaining what happened here and what the important aspects are. The Telegraph did a pretty poor job.
posted by grouse at 2:14 PM on June 14, 2015 [3 favorites]

I was already worried about 50 percent. 5 is much better.
posted by Mr. Yuck at 2:40 PM on June 14, 2015 [1 favorite]

This is more of a question to those who know better, but if there is a whole other mechanism which regulates our gene expression, isn't epigenetic kind of a misnomer? Sort of like ripping the conditionals out of computer code and calling *that* code and the conditionals epi-code.
posted by smidgen at 6:07 PM on June 14, 2015

I've read/heard of similar issues surrounding trauma affecting genetics... Which considering the level of abuse some population have undergone for who knows how many generations, makes me a bit queezy.
posted by edgeways at 6:18 PM on June 14, 2015 [1 favorite]

Sort of like ripping the conditionals out of computer code and calling *that* code and the conditionals epi-code.

Lots of resistance to Lamarck being right.

Lamarck was right. Not entirely, of course. But the whole "survival pressure explains all variation" is actually wrong.

Biology: There's always another bit.
posted by effugas at 8:51 PM on June 14, 2015 [1 favorite]

"Poor lifestyle" is a hell of an editorial insertion.
posted by gingerest at 12:03 AM on June 15, 2015 [8 favorites]

In fact, around five per cent of our genetic code carries traces of past events, meaning that trauma, poor diet or poor lifestyle choices may by leaving a devastating legacy for children and grandchildren.

So one might assume that the avoidance of trauma, proper diet, and "good" lifestyle choices can have a constructive legacy for children and grandchildren.

Tolstoy had it right: All happy families are alike, but each unhappy family is unhappy in its own way.
posted by three blind mice at 2:24 AM on June 15, 2015 [2 favorites]

I think the weird thing about this article is the inherent presumption that all change is damage -- that our genome is some sacrosanct document that must be protected from alteration by mere events in life.

Yeah. Adaptation is pretty awesome, however it may come.
posted by effugas at 3:09 AM on June 15, 2015 [2 favorites]

Sort of like ripping the conditionals out of computer code and calling *that* code and the conditionals epi-code.

As I understand it, it would be more like having configuration files that can be rewritten by the software in response to environmental input.
posted by lodurr at 9:44 AM on June 15, 2015

Apparently, there is nothing, not even a list of the names of the DNA nucleotides, that can't help jazz up an article by being juxtaposed with a picture of a naked woman. Stay classy, Telegraph.
posted by gurple at 10:12 AM on June 15, 2015 [1 favorite]

Lysenko would be smiling, but his ideas were, to put it kindly, unscientific and at the time unsupported by any evidence, and of course resulted in famine, hardship, and death for millions as they tried to grow crops and animals in unsuitable climates to prove his "theory." Even in the USSR, his work was widely and quitely discredited by the end of the 1940s, though the politically motivated education and experiments didn't end until the mid-1950s. Lysenko was wrong, in every respect, and would have rejected the Mendelian genetic interpretation of the more more recent discoveries in favor of his own self-named Lysenkoism, relying on on woo and a belief in the superiority of all things Communist rather than hard science.
posted by Blackanvil at 10:22 AM on June 15, 2015 [1 favorite]

Genomic imprinting works by retaining methylation.
posted by francesca too at 10:25 AM on June 15, 2015

Lysenko would be smiling...

Actually I kind of think he wouldn't.

Based on the woo-adherents I've known, the first thing they do when presented with something that supports their general ideas is to tear it apart on the details.

So given that Lysenko was a guy who was willing to go to extreme lengths to force his ideas into practice, I'm thinking he'd be likely to go ballistic on epigenetics as a bunch of misinformation clouding the real truth, which we'd understand if we'd just accept the truth of his own theories....
posted by lodurr at 11:31 AM on June 15, 2015 [1 favorite]