A vegetarian diet could cause long-term genetic changes | Hacker News Reader

A vegetarian diet could cause long-term genetic changes

sciencealert.com

90 pointspitchka38 comments

This isn't particularly surprising once you understand that your DNA isn't immutable. Lots of things can change you genetically. For example, a male smoker can have changes in his DNA that increases the probability that his children could get cancer[1], and the grandchildren of a woman who smokes have a higher risk of asthma[2]. Everything that has a significant impact on your body probably changes your genetic make-up in some small way.

[1] http://www.medicalnewstoday.com/articles/247104.php [2] http://www.eurekalert.org/pub_releases/2015-09/elf-gsh092515...

Lamark got it right XD

And you got it wrong: Lamarck

epigenome

There's a related RadioLab episode on this topic. A Scandinavian researcher showed that if you underwent caloric restriction in your adolescence, then surprisingly, your descendants are less likely to suffer from heart disease, diabetes, and other illnesses related to diet.

http://www.radiolab.org/story/251876-inheritance/

Title is misleading. This is across an entire population over generations. Should be changed to something similar to that. This sounds like it happens to an individual if they eat a vegetarian diet for a long period of time.

Title isnt misleading. The title literally said what its content contained.

A vegetarian diet carries a certain implication, specifically that we're speaking about such a diet in one person.

"Widespread vegetarian diets among a population could cause changes over time" is wholly different and apparently more accurate.

The implication is subjective.

The title said "A" Vegetarian diet. It never referenced whom, what gender or the scope of the study, so in a literal sense, the title wasnt misleading at all.

I took the implication "A" Vegetarian diet, as in any or all contexts with in a long time period.

"A" implies that the effect would be felt in a singular case.

Not if you know the difference between genotype and fenotype.

*phenotype

And the Venn diagram for the target market of this website excludes those who do.

A title can be literal and be misleading. this is the role of connotation and context.

They should have analysed Pakistanis with the Indians many of which few generation ago were vegetarians before converting to Islam. Would really show how many generation it takes for the dna to change etc

True, though there's a lot of this going on in just the Indian population as well. Generally, people tend to eat more meat as incomes rise. That is true in the west as well as the east.

xbmcuser is talking about tradition of vegetarianism due to faith, which does not linearly increase meat consumption in certain groups. Actually the traditionally vegetarian groups tended to be economically above average in India.

Upper (rich) class in India is mostly vegeterian, including current prime minister. Historically, outclass eat meat as they were cut off from farm based civilisation.

That pattern, to the degree it exists, is relatively recent, compared to the evolutionary time scale. It is no older than the religious encoding of vegetarianism in India, which is ~2k years old, and even that was widespread only at a later date.

A better explanation is to compare to other populations with similar environments, like Africa. In fact the graphic in the article shows a similarly higher rate of the alleles in question.

For those who are interested, here's the article (open access):

http://mbe.oxfordjournals.org/content/early/2016/03/09/molbe...

It's worth pointing out that here "genetic changes" means evolutionary adaptation over many generations, not some sort of mutagenic effect

"there's also an increased risk of the creation of inflammatory acids linked to heart disease and colon cancer, especially in combination with vegetable oils."

But last week red meat gave us colon cancer!?!?

There. Is. No. Data. Flow. From. Phenotype. Back. To. Genotype.

It just does not work that way. Mutations could be favorable and unfavorable, but there is no mechanism that "adaptations" are encoded back into genome.

Some random mutation which persisted in one population and wiped out in another has been selected due to environmental factors, such as climate and availability of food sources, does not imply that it is necessarily better or advantageous for a different environment.

And, of course, a diet could not cause genetic changes. Mutations could be selected in a population within some particular environment or wiped out in another.

That isn't the claim they are making, because that would be a huge claim. I think the author knows that the occurrence of mutations aren't present because they are eating veggies. Instead, they mean they are being selected because they are eating veggies.

Correlation is not causation.

Phenotype changes can affect the rate of mutations and lead to faster evolution allowing to discover in time a trait essential for survival under new conditions. Although indirect, this is still a data flow. Without a particular phenotype the population would simply not able to discover in time the necessary mutation and survive.

Nope. Mutations in a single organism are almost irrelevant. They must propagate via offsprings (be selected in meiosis) and eventually spread throughout population, otherwise they will be lost. This is a protective mechanism without which there will be no stable traits and no complex organic life at all.

I fail to see how this disproves that phenotype can alter genotype through the speed of mutations. The point is that after environmental change there is a limited timeframe when a population can develop a trait essential for survival in the new situation. If the rate of mutations is low, the whole population will simply die.

However, if by phenotype changes the mutation rate can be increased, then the population can adopt. In that case the new genotype trait essential for survival will be available only in offspring coming from phenotype that allowed faster rate of mutations. This is a data flow from phenotype to DNA.

Mutations are random. Increasing mutation rates for such a complex organisms as humans is the same as increasing the probably of cancers and negative mutations. Only bacteria could afford this.

Species whose mutation rate fluctuates according to its diet wouldn't last too long.

Oversimplified models doesn't represent mostly-stohastic reality, especially in genetics.

And, still, the one way flow of information is the fundamental principle which makes complex organs such as heart, brain or liver possible.

Everything which contradicts a fundamental principle is merely a mental abstraction. Or a story.

That claim is turning out to have exceptions: http://learn.genetics.utah.edu/content/epigenetics/inheritan... In some circumstances, epigenetic markers are retained and passed to the next generation.

Ok. Couple of points: (1) A vegan diet can't "cause" genetic changes. My diet is a part of my behaviour, and short of exposing myself to lethal amounts of radiation or carcinogens, I can't modify my genes with my behaviour. (2) However, if we modify an organism's environment (by, say, restricting what is available to eat), then over many generations, we should expect that organism's descendants to adapt to that change. I guess more experimental confirmation of evolution is nice, but it's not really very exciting. [Edit: Minor grammar picks]

Sorry, but that's just wrong.

Thanks. I really appreciate your nuanced critique of the argument.

"...I can't modify my genes with my behaviour."

This is incorrect. Your behaviour changes your environment (both directly and/or by exposing you to new/altered environments) and your environment modifies how your genes are expressed. See the wikipedia page for Epigenetics:

"Epigenetics [...] is the study, in the field of genetics, of cellular and physiological phenotypic trait variations that are caused by external or environmental factors that switch genes on and off and affect how cells read genes instead of being caused by changes in the DNA sequence. Hence, epigenetic research seeks to describe dynamic alterations in the transcriptional potential of a cell." [1]

These mechanisms act on an individual and are separate from Darwinian adaptation.

[1] https://en.wikipedia.org/wiki/Epigenetics

EDIT: "and your environment modifies your genes" -> "and your environment modifies how your genes are expressed"

Epigenetics is about gene expression, the genetic code isn't changed.

The Danish/ Swedish famine study that first proved epigenetics was real showed that starvation during puberty affected the height of granchildren by switching off genes that were still present. The third generation is unaffected precisely because it is not genetic change.

Enviroment only affects genes by reproduction, successful genes are inhereted or not - there is no change in genes during a lifetime - that would be Lamarkism and he was wrong.

Lifestyle affects methlyation markers,which are added and change gene expression for a few generations.

The underlying genes are not changed and are still inhereted, once the methlyation 'wears off' everything will be as before.

Thanks for that. When I wrote "and your environment modifies your genes" I should have written "and your environment modifies how your genes are expressed."

I'll amend my comment.

There are a lot of assumptions in there. For instance, those methylation marks may in fact lead to changes in the DNA. Epigenetic silencing is possibly associated with gene duplication: http://link.springer.com/article/10.1007/s00239-002-2446-6

Thank you for clarifying that the statement "the environment doesn't modify how your genes are expressed" is incorrect. Thankfully, neither I nor the posted article made that statement.

Reflecting your edit, correcting your statement, thanks. Perhaps you could also point out that your edit refutes your criticism of the OP?

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