# Is it possible to communicate through DNA?

Alternatively, could DNA be a language (the normal coding that exists within DNA to tell it what to build) that is capable of telling us anything.

This question is based off of this article about aliens may be able to communicate to us through DNA

There isn't a reason why not.
Computers communicate with just 1 and 0.
DNA has 4 chemical bases, and humans have around 3 billion base pairs.

There are sections of human DNA that are left over from ancient viruses, so it's not a great leap to think that a message could be encoded in DNA, put into a virus and inserted into a person's genome that way.

Then you'd only need to know where to look, have the equipment to extract and sequence it, and the key to decode it.

Edit: Encoding
The base chemicals for DNA are adenine (A), guanine (G), cytosine (C), and thymine (T).

If we arbitrarily assign them each a base 4 number to make a key:
A = 0
G = 1
C = 2
T = 3
Then we can use them in a message.

Take the phrase "Hello World".
In binary (base 2) that computers use, it would be 01001000 01100101 01101100 01101100 01101111 00100000 01010111 01101111 01110010 01101100 01100100

In base 10 (normal) that would be "H"=72 "e"=101 "l"=108 "l"=108 "o"=111 " "=32 "W"=87 "o"=111 "r"=114 "l"=108 "d"=100

In base 4 it would be 1020 1211 1230 1230 1233 0200 1113 1233 1302 1230 1210

And using our key, it would be GACA GCGG GCTA GCTA GCTT ACAA GGGT GCTT GTAC GCTA GCGA

You could even encode a kind of primer in to let people figure out what the key is if they don't have it, similar to something SETI might use to help aliens figure out how to read a message we send them.

• A better example might be “TO LIVE, TO ERR, TO FALL, TO TRIUMPH, TO RECREATE LIFE OUT OF LIFE.” rather than Hello World. New medium, new tradition, it would seem. – JDługosz Sep 23 '16 at 6:17
• @JDługosz yeah, but that's pretty long... If was going to use something like that is probably write a program to do the work instead of doing it by hand. – AndyD273 Sep 23 '16 at 13:32

We do, it's called sex.

Without going too deep into the details, when a spermatozoa meets an ovum, that is, in effect, communication using DNA. What is being communicated is of course information about the father's genetic makeup, and that's incorporated into a new individual down the line.

There are also other creatures, such as bacteria, that are able to ship their own DNA into their friends in what is called horizontal gene transfer.

Finally, on a cellular level, DNA (or rather, mRNA, but the practical differences are in this case negligible) is used to communicate between the various processes in and between our cells.

All of that aside:

Is DNA a viable store of information? Yes, manifestly.

Can it be used to communicate? Again, yes, manifestly.

But is it a good means for communicating between creatures? Well… No. It's not.

First of all, DNA is expensive. Not in terms of dollars and cents, but just energetically. Making DNA takes a lot of energy, storing DNA takes energy, and reading DNA takes energy.

While it does have the benefit of persistence, so does a lot of simpler, cheaper chemicals such as hormones, for creatures living in the meter realm of existence (such as ourselves) DNA communication would just be an enormous hassle.

It works for bacteria because they are a lot more similar in size to the DNA molecules than we are, and so can, in a sense, manipulate them directly. For even something in the millimetre realm (say, an ant) this would already be completely infeasible, which is why ants use simpler hormones to communicate.

• One benefit of communicating via DNA is that it would be really hard to detect and decode. As @ApproachingDarknessFish pointed out, scientists are working on DNA computers and DNA storage, and ways to do genetic modification using retroviruses. It wouldn't be a great leap to use people as couriers, and their DNA as the payload. They wouldn't even need to know about it. Poke a person that's going to the right country, and have someone on the other side take a blood sample. It wouldn't be for casual conversations though. That would be impractical as you say. – AndyD273 Jul 19 '16 at 15:41
• @AndyD273: Trusting a channel of communication to be secure is rarely a good idea, especially when you're trusting it because you expect people don't know about it. Anything secret messages can do, encryption can do better. – Williham Totland Jul 19 '16 at 16:04
• Why not both? Say a spy uses an unsuspecting person as a mule to carry a DNA encoded message out of the country. The first layer of defense would be obscurity, with thousands of travelers to screen for the message, the anti-espionage people would have a hard time finding the right person. Then with billions of base pairs to look at it would be really hard to find the message embedded inside the noise. And if you did find it, you'd have to figure out the encoding scheme used, which might be anything. And if you encrypted it before encoding it, that would make things even harder. – AndyD273 Jul 19 '16 at 16:17
• Another reason to encode things in DNA is for it's ability to be passed on. Say you are planning for the end of civilization. You encode the library of congress and give it to everyone as an inoculation. The bombs fall and wipe out most stuff. Years and years go by, and civilization rebuilds. They rediscover how to read DNA and find the records, and all that lost information is found again, a gift for the future. – AndyD273 Jul 19 '16 at 16:21
• @AndyD273: So you're talking about retroviruses rewriting the DNA in every cell of their body? That seems… extremely invasive. And if any part of the DNA looks like it starts a gene… Suddenly you have the molecular machinery of the cell building strange, random proteins, or trying to put together a person in very strange ways? – Williham Totland Jul 19 '16 at 16:49

There are a bunch of good answers here that are clearly showing that information beyond genetics can be encoded in DNA and those are indeed answers to the question as it is phrased. But the question made me wonder about DNA, not as written language, which is implied by the asker, but rather as "spoken" language - I doubt that any of us would find the coding discussed so far a suitable and satisfactory substitute for what we call language in our daily lives. So I think the we need to answer (at least I want to answer), "can DNA be used by a species just the same way we use spoken language or sign language". Dynamic, interactive, adaptive symbolic code capable of communicating, on a contemporaneous basis, information, emotion, etc.

Can DNA have a syntax? A grammar? Yes, we know genetic coding already has both syntax and grammar so those tools exist for our DNA language.

We need a organ to "speak" our language and an organ to "hear" our language. We can certainly imagine such organs. Our cellular machinery can already perform the tasks of writing (copying) and reading DNA strands. But our imagined language organs will need to be much more nimble. Our speech organ will need to assemble DNA strands based on inputs from our nervous system; Building DNA strands representing words and sentences and then emitting them to the medium between the speaker and the listener (air, water, ??). Such an organ would probably need to emit many copies of our sentence since our words are traveling in matter packets (not energy waves) and cannot be "heard" until the molecule of our sentence arrives at the receivers hearing organ. Sending just a single sentence molecule would result in a very poor chance of ever being heard! We must puff our sentence out a thousand times simultaneously like pollen from a flower on the wind. Of coarse, our words and sentences will need to contain a grammar similar to a time stamp. If I say "Hi, How are You?" 1000 times, and the recipient receives 120 of those "Hi, How are You's?", I don't want him to "hear" all of them. I need to give him a grammar to hear the first "Hi!" and filter out all the rest as noise.

So, on the "hearing" end of the conversation, we need an organ filtering the media between us and the "speaker" scanning for floating bits of DNA. Assuming we are on a planet that uses DNA for genetics, not just language, there is going to be a lot of DNA genetic material floating about. So our DNA language grammar must make a clear distinction between a word or sentence and genetic DNA which is just noise to be filtered out and ignored. If this filtering happens at the biological level of the organ itself, then calling it a "grammar" may be misleading. For instance, the organ might only bond with DNA strands that begin with a complex 100 nucleotide sequence. Any DNA strand that does not have this telomere at the beginning/end does not bind and is not "heard". Either way, biological or grammatical, the hearing organ responds to the coding in the captured and read DNA strand by activating the hearer's nervous system. Just as our ears do for us.

So now that we have imagined the machinery for a species to have DNA molecule based language, we can imagine some consequences and advantages...let's go scifi.

In the case where we use the biological filters on our organs (complex telomere tag is required or molecule is not read because it wont bind) any individual who suffered a mutation that either resulted in there speaking organ coding the wrong telomere or there hearing organ failing to bond to the correct telomere would be rendered either "mute" or "deaf".

Conversations would be subject to very different rules when your words can be blown with the wind and be heard miles away! Or when no one up wind of you can hear you no matter how loud you shout. Also, since your words and sentences are subject to the vagaries of the wind or just random distribution by Brownian motion, our language and our nervous system will need to evolve to deal with the fact that our sentences will often not arrive with the same timing, or even in the same order, that we spoke them in!

And for that matter, what is a shout? Producing 100,000 DNA sentence copies at a time? Making a whisper the creation of just a few copies?

As this species evolves, will they evolve some level of encoding to enable private conversation? Perhaps the hearing organ can hear a DNA molecule starting with any telomere sequence, but it can hear (bind) only one possible telomere at a time. So most conversations happen with telomere Alpha. But when two or more individuals want to talk voce sotto, they switch over to telomere Lambda or Omicron. There words are still arriving at the hearing organs of others, but are ignored by all who are not "listening" for Omicron.

What is a recording device on this planet? Can biological microbes be engineered to reproduce / record conversations by replicating the DNA that makes up the sentences and words?

Since words are matter, not energy, they potentially have a lifetime far beyond what we are used to. You could capture the last words of your mother in a jar, and hear them again...and again....and again for years - until the last of the molecules of that sentence were used or lost. NOT just a recording - the actual voice of your mother, her spoken words from her "mouth", unchanged just as if she was there with you in the room.

Specters of conversations might linger in buildings for years or generations. Imagine closing a door in Philadelphia's Liberty Hall and dislodging from a dusty rafter a few sentences between Ben Franklin and Thomas Jefferson arguing over a paragraph in the Declaration of Independence! As those sentences/molecules drifted into your "ear", you would hear Franklin and Jefferson - their words in their voices - unchanged from the moment they spoke them 250 year ago. The occupations of archaeologist and historian would be something quite different.

Finally, since DNA is still the mechanism for genetic information encoding and transmission, can these creatures "speak" genetic information? For instance, could a lover "whisper" a hormone that caused the object of there affection to feel flush? Or an RNA strand, inhaled by the subject which caused the production of the hormone by his/her own limbic system. Or could a rival encode and surreptitiously breath a virus onto his victim? Or, the most insidious end to this line of reasoning...could a sentence itself be encoded in such a way that hidden within it were the very instructions that caused the hearer's cells to produce the virus in their own body?! Just like sticks and stones, on such a world, words can kill you!

It's entirely possible in fact DNA is practically a biological language. True it's not half as many "letters" as English does but machine code only uses zeros and ones to communicate and that works just fine.

Since the DNA is your blueprint for what is built... I don't see why your blueprint couldn't eventually be complex enough to 'build/grow' not only a 'blank' brain, but one that already contains completed neural pathways.