
Astronaut’s DNA No Longer Matches His Identical Twin’s After Year Spent in Space - Mononokay
http://ktla.com/2018/03/14/astronauts-dna-no-longer-matches-his-identical-twins-after-year-spent-in-space-nasa-finds/
======
loufe
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
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.

~~~
toufka
It has started to come up a lot recently in order to produce the above-like
click-bait headlines. Here's my standard copy-pasta quoting myself from when
it shows up around here:

Epigenetics. It's the make-file for your genetic source code. Certain
conditions can cause certain parts of your genetic code to be uncommented or
commented-out within any given cell or set of cells. There are actually a
number of different kinds of 'comments' (histone modifications [1]) - each set
of marks are particular to a different compiler, in different contexts. And
these comments/marks are copied with some fidelity to daughter-cells/children
along with a high-fidelty copy of the underlying genetic code itself.

So the genes (DNA) themselves are not being heritably altered, rather the
recipe for which gene is produced, when, and where can be subtly changed. But
again, the same mechanisms that permit the change in expression of those genes
during a lifetime (of an organism, or a cell) can be subsequently changed in
the next just as easily.

In this way you can store the code for some trait or capability over many
generations without having it always be running. It can manifest itself in
individual organisms or cells as having very different phenotypes even while
possessing the same underlying genetic code.

[1]
[https://en.wikipedia.org/wiki/Histone_code](https://en.wikipedia.org/wiki/Histone_code)

~~~
Retric
It's arguably much closer to RAM than a make file.

Picture a Glucose detector wrapped around a DNA segment that encodes something
to break down Glucose. If you zero Glucose inside the nucleus you stop
producing stuff to deal with it.

The difference for this analogy is cells never stop compiling. On the other
hand if you think of cell division as a reboot it's a better fit.

------
gabeiscoding
A much better source for those with an interest in the science is Chris
Mason's slides from his recent talk[1] at genetics conference (AGBT) about
this that he shared on twitter[2].

He's a great speaker, and a cool guy and tackles some of the most interesting
(at least to hear about) science in genomics

[1]
[https://www.dropbox.com/s/sfg6rdmgxjwdpil/Mason_NEB_talk_AGB...](https://www.dropbox.com/s/sfg6rdmgxjwdpil/Mason_NEB_talk_AGBT_2018.pdf?dl=0)
[2]
[https://twitter.com/mason_lab/status/964151387687972864](https://twitter.com/mason_lab/status/964151387687972864)

------
gus_massa
[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...](https://www.nasa.gov/mission_pages/station/research/experiments/2104.html)

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](https://en.wikipedia.org/wiki/DNA_methylation)

~~~
psychobabble
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...](https://theconversation.com/epigenetics-can-stress-really-change-your-
genes-55898)

\- [http://sitn.hms.harvard.edu/flash/2017/stress-induced-dna-
mo...](http://sitn.hms.harvard.edu/flash/2017/stress-induced-dna-modification-
may-play-role-mental-illness/)

\-
[https://www.scientificamerican.com/page/sponsored/nestle/how...](https://www.scientificamerican.com/page/sponsored/nestle/how-
diet-can-change-your-dna/) 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](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](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...](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080029284.pdf)

And more poignantly, from
[https://www.vencoreweather.com/blog/2017/6/26/1200-pm-
cosmic...](https://www.vencoreweather.com/blog/2017/6/26/1200-pm-cosmic-rays-
continue-to-rise-as-solar-cycle-approaches-next-minimum) ( 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.

~~~
gus_massa
I am not a biologist, so my answer may have a mistake ...

Radiation and cosmic rays produce random mutations, where one of the bases of
the DNA is changed by another base. (IIRC the radiation breaks the old base,
and when the copy or correction enzymes see the mess, they may make a mistake
and use the wrong base.)

Methylation is on purpose. Some part of the cell "decides" to enable or
disable a gen, and send the correct enzymes to add or remove the methyles in
the bases of the specific part of the gene.

(There are also some arm races between bacteria and virus that attack
bacteria. The bacteria has an enzyme that split the DNA at points with some
specific patterns, to try to kill the virus that enter the cell. The parts of
the DNA of the bacteria with this pattern are methylated, so the enzyme
doesn't attack the DNA of the owner.
[https://en.wikipedia.org/wiki/Restriction_modification_syste...](https://en.wikipedia.org/wiki/Restriction_modification_system)
)

------
tofof
From the Nasa press release, 93% of the genetic expression pattern (very
different than "DNA") remained the same before and after spaceflight, while 7%
was altered.

Search for "93%" in [https://www.nasa.gov/feature/nasa-twins-study-
investigators-...](https://www.nasa.gov/feature/nasa-twins-study-
investigators-to-release-integrated-paper-in-2018)

------
sathackr
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
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.

~~~
everly
"DNA is not fixed, they change all the time."

Then why is it significant that time in space changed it?

~~~
mikhailt
It’s the rate of change compared to his twin on earth. This ars article
explains better: [https://arstechnica.com/science/2018/03/scott-kellys-
medical...](https://arstechnica.com/science/2018/03/scott-kellys-medical-
monitoring-has-spawned-some-horrific-press-coverage/)

------
mirimir
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.

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make3
"Answer a question in this survey to continue reading this content" Really? no
thanks

------
skookumchuck
More likely aliens have replaced him with a pod person to infiltrate NASA.

------
gowld
> 93% of Scott's genetic expression returned to normal once he returned to
> Earth,

How much was abnormal during the trip?

------
lithos
That really clever they put the ask for notifications button over the top of
the close ad button.

------
tyingq
Sounds like the genesis for a new sci-fi movie.

------
zaroth
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
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.

~~~
zaroth
Yes, this was on my iPhone. I always hav Safari set to Private mode so I think
there is no history.

