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Astronaut’s DNA No Longer Matches His Identical Twin’s After Year Spent in Space

176 points| Mononokay | 8 years ago |ktla.com | reply

55 comments

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[+] loufe|8 years ago|reply
The article headline is practically fake news. The article isn't very clear on it either. It's not someone's DNA that changes, that would be astounding if all the trillions of cells in your body underwent the same genetic mutations. No, this is a change in epigenetics. The things that change what parts of your DNA are expressed and are much easier to coordinate, change, and adapt in the short-term.

Epigenetics are not that foreign a concept that people should assume the average reader won't understand them or will find it any less amazing.

[+] purple-again|8 years ago|reply
I consider myself to be very armchair scientifically literate (zero real applied knowledge but I have consumed just about all of the pop culture created on the subject in the last 30 years).

I have never heard the word epigenetics until now and am still confused about what exactly happened to this guy.

[+] koonsolo|8 years ago|reply
Ok, that explains a lot, because my imagination was going wild with these 2 things:

According to the article: Preliminary results from NASA's Twins Study reveal that 7% of astronaut Scott Kelly's genes did not return to normal after his return to Earth two years ago.

According to my memory, and now looked it up: Chimps and bonobos in particular take pride of place as our nearest living relatives, sharing approximately 99 percent of our DNA, with gorillas trailing at 98 percent.

Good thing they put a picture in the article of the guy, haha.

[+] mrmondo|8 years ago|reply
While I think it’s important to disagree with news that might be less than factual and better yet - think with a skeptical mindset, I think it’s rather anti-intellectual to blanket misleading or factually lacking news as ‘fake news’.
[+] teekert|8 years ago|reply
Exactly, I would expect this person to perhaps have some additional mutations (in his superficial tissues so no body wide mutation of course) due to radiation, or perhaps due to selective pressures working differently on them in 0 G. Also I'd expect expression changes (RNA quantity changes), also related to 0 G or maybe to his diet. Also, it is often claimed that chimp DNA is only 1% different from ours. Which is also bull of course, it depends, (as here) on how difference is defined. The telomere story is interesting but from the text it sounds like we already expect that from radiation and calorie restriction.
[+] im3w1l|8 years ago|reply
> would be astounding if all the trillions of cells in your body underwent the same genetic mutations.

spoiler: they won't all undergo the same epigenetic changes either.

[+] Erlangolem|8 years ago|reply
I think the issue for the article is that identical twins are not epigenentically identical to begin with, time in space and life in general will only tend to magnify that. In essence, the headline is doubly misleading.
[+] gus_massa|8 years ago|reply
[I'll copy my comment from dupe story that didn't get any traction.]

The article avoids all the interesting technical details. In case you are wondering if this is possible and how much of this is an exaggeration, the title of the research article is "The Landscape of DNA and RNA Methylation Before, During, and After Human Space Travel (Twins Study - Mason) - 09.27.17" https://www.nasa.gov/mission_pages/station/research/experime...

Methylation is an usual process that the cells use for enabling and disabling genes expression. It's reversible, somewhat permanent and somewhat inheritable. If you like a bad analogy, it's like making a change in the bios setup of your computer or updating the configuration of the wifi-router. It's not a firmware upgrade or a hardware modification. More info: https://en.wikipedia.org/wiki/DNA_methylation

[+] psychobabble|8 years ago|reply
Oh heck, me too - since I was responding to your only comment just minutes ago, here is again :)

Maybe, but what is really causing the DNA methylation? The article pins it mostly on epigenetics or environment, the 'stress of space travel', including dietary constraints and oxygen levels all of which are valid.

- https://theconversation.com/epigenetics-can-stress-really-ch...

- http://sitn.hms.harvard.edu/flash/2017/stress-induced-dna-mo...

- https://www.scientificamerican.com/page/sponsored/nestle/how... ooh, sponsored article, didn't catch that the first time.

However, the CNN article only briefly mentions 'radiation' as a factor and likely is lumping that into the 'stressful environment' case repeated several times.

Realistically, cosmic rays or radiation are far more likely to the be prevailing indicator for DNA disruption but are not plainly disclosed here. Despite much research having been done on this specific topic.

Wikipedia states: https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays "The potential acute and chronic health effects of space radiation, as with other ionizing radiation exposures, involve both direct damage to DNA, indirect effects due to generation of reactive oxygen species, and changes to the biochemistry of cells and tissues, which can alter gene transcription and the tissue microenvironment along with producing DNA mutations."

From this paper: https://arxiv.org/abs/1406.6641 "In the present paper, we suggest the BNR as a cause of genetic “fails” in living cells, that is one of the possible origins of the so called spontaneous mutations. Cells exposed to the shower of electrons and ions, caused by the collision of a neutron and a proton of water, could be annihilated or experience a permanent damage, in particular, a damage in the DNA."

Cosmic radiation detrimental effects to DNA confirmed by NASA in this study: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/200800...

And more poignantly, from https://www.vencoreweather.com/blog/2017/6/26/1200-pm-cosmic... ( do not read full link if you are easily panicked ): "... there are other consequences of increasing cosmic rays according to “Spaceweather.com” including the penetration of commercial airlines, dosing passengers and flight crews enough that pilots are classified as occupational radiation workers. [Dose rates are expressed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x]"

Sorry for the data dump, I just happened to be researching cosmic ray effects the past few evenings and have collected many interesting facts on the topic. The most I have concluded at this point is that humans, as currently derived, are not made for space travel.

[+] sathackr|8 years ago|reply
I don't understand why an identical twin was needed to learn this.

Couldn't an astronaut's DNA be sampled before and after a mission and compared?

[+] mikhailt|8 years ago|reply
How would you rule out age-related changes since this specific astronaut was in space for a year? DNA is not fixed, they change all the time.

It is always better to have more data points to rule out several variables, especially considering that it is rare to have an astronaut with a twin sibling.

[+] lithos|8 years ago|reply
Some accounting for a year of aging. Though the news press is probably more scientifically significant.
[+] telchar|8 years ago|reply
Well, consider the counterfactual of what would have happened to the astronaut's DNA if he hadn't gone to space. We don't know how it would have changed, so we can't compare it directly. Since we needed to do the experiment I'm guessing our knowledge DNA was not sufficient to predict that, so it makes sense to use a twin to get the closest proxy to the counterfactual that we can.
[+] 88e282102ae2e5b|8 years ago|reply
Sure, but everyone is accumulating mutations all the time, so you need a control on the ground to see if space itself is affecting the mutation rate.
[+] mirimir|8 years ago|reply
The article is muddled.

> To better understand the genetic dynamics of each twin, Mason and his team focused on chemical changes in RNA and DNA. Whole-genome sequencing revealed that each twin has more than expected unique mutations in his genome -- in fact, hundreds.

So both experienced hundreds more unique mutations? But OK, let's say that it was Scott Kelly who experienced more mutations. But which tissues did they sample? Sperm?

> Preliminary results from NASA's Twins Study reveal that 7% of astronaut Scott Kelly's genes did not return to normal after his return to Earth two years ago.

This is about gene expression, not necessarily mutations. And it's the key take home. Given that we've known for some decades that radiation causes mutations.

[+] make3|8 years ago|reply
"Answer a question in this survey to continue reading this content" Really? no thanks
[+] skookumchuck|8 years ago|reply
More likely aliens have replaced him with a pod person to infiltrate NASA.
[+] gowld|8 years ago|reply
> 93% of Scott's genetic expression returned to normal once he returned to Earth,

How much was abnormal during the trip?

[+] lithos|8 years ago|reply
That really clever they put the ask for notifications button over the top of the close ad button.
[+] tyingq|8 years ago|reply
Sounds like the genesis for a new sci-fi movie.
[+] zaroth|8 years ago|reply
Anyone else getting the “Congratulations you are a winner” ad spam / malware which takes over the page and forces a redirect?

I run into this on news sites several times a week. I assume these are ads which are sneaking by the ad networks filter and running scripts on the page, just not sure how they are so damn pervasive?

If these ads aren’t being paid for with stolen credit cards, then why aren’t they people buying them getting slammed with CFAA charges? Is it that hard to track these clowns down?

[+] dahdum|8 years ago|reply
I get these frequently too, especially on IOS devices. If you wipe your browser history it stops happening, so I assume they are doing some checks against Ad Network filters.
[+] namanyayg|8 years ago|reply
Are you sure you don't have malware on your system? I haven't experienced a redirect ad in basically forever.