DNA Encode a String

Question

Challenge

You must write an encoder (and a separate decoder) which takes a string as input and outputs the string encoded in the style of a strand of DNA.

DNA

DNA is made up of four types of nucleotide:

• Adenine (A)
• Thymine (T)
• Cytosine (C)
• Guanine (G)

Adenine and thymine pair up together to make AT or TA. Similarly, cytosine and guanine pair up together to make CG or GC.

Let's call these pairs units. This means that your encoded string is only allowed to contain the four units AT, TA, CG and GC.

This means that:

ATTAGACG

Would be invalid because it contains the unit GA, which is impossible.

Similarly,

TAGCGCCGATA

Is invalid because the final A does not have a thymine to pair up with.

Example

You must encode the following example text and use its encoded length as part of your score:

I have a friend who's an artist and has sometimes taken a view which I don't agree with very well. He'll hold up a flower and say "look how beautiful it is," and I'll agree. Then he says "I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing," and I think that he's kind of nutty. First of all, the beauty that he sees is available to other people and to me too, I believe. Although I may not be quite as refined aesthetically as he is ... I can appreciate the beauty of a flower. At the same time, I see much more about the flower than he sees. I could imagine the cells in there, the complicated actions inside, which also have a beauty. I mean it's not just beauty at this dimension, at one centimeter; there's also beauty at smaller dimensions, the inner structure, also the processes. The fact that the colors in the flower evolved in order to attract insects to pollinate it is interesting; it means that insects can see the color. It adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic? All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don't understand how it subtracts.

Bounty

If you answer this challenge in the language DNA#, I will offer a 100 to 200 rep bounty.

Rules

Your encoder and decoder programs must work for any string supplied. Therefore, your encoder must produce a genuine encoding and your decoder should not simply hardcode the example text.

You must support all printable ASCII characters:

 !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~

If you can support more characters, that is acceptable.

Scoring

Your score is how long in characters (not units) the encoded version of the above text plus the length in bytes of your decoder and your encoder.

Winning

The program with the lowest score wins.

Answer 1

Pyth, 5152 + 21 + 23 = 5196 bytes

Encoder

sm@c4s_B"ATCG"djC.ZQ4

Try it here

Decoder

.ZCimxc4s_B"ATCG"dcQ2 4

Try it here (Input too long to link, put output of first in quotes in the input box)

Compresses the input and converts it from base 256 into an integer. Then converts into a sequence of base 4 numbers and chooses from ['AT', 'CG', 'GC', 'TA']

Answer 2

DNA# : 10216 + 852 + 384 = 11452 bytes

This is not exactly tested, as I haven't gotten a hold of a working interpreter... There are probably mistakes

I use a simple brute force approach so far where each character is read in, then broken up into 2 bit blocks with AT = 00; TA = 01; CG = 10; GC = 11. The sample text is 1277 ASCII characters, and it takes 4 codes (2 bits) to encode each 8 bit char: 1277 * 4 * 2 = 10216 bytes

Encoder

852 bytes - line form

GCGCGCTAATATATTAATTAATTAATTAATTAATTAATTAATTATACGCGCGATATTAATATGCATGCCGCGGCTACGATATGCCGCGATATATTAATTAATTAATTAATTAATTAATTAATTATACGCGCGATTAATATATTAATTAATTAATTAATTAATTAATTAATTAATTATACGCGCGATTAATTAATTAATGCATGCGCTAATATATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATATATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATGCATGCATCGGCCGGCTAATATATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATCGATATATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATGCATGCATCGGCCGGCTAATATATTAATTAATTAATTAATATATCGATCGATCGATCGATGCATGCATCGGCCGATATGCATATATGCATATGCATGCATGCATCGGCTAATTAATATTAATATGCATGCCGCGCGATATGCCGCGTACGATGCCGCGATGCATGCTATAATATATATCGCGATATATATGCTAATCGGCCGATTAATTAATTAATTAATGCCGATATATCGCGATATTAATATGCATGCCGCGATATGCTAATCGGCCGATATGCTAATCGGCCGGCCGATGCATGCGCCGATGCATGCGCGCGCCG

224 bytes - symbol form:

,[>++++++++*=X>:=<<X[/=<X>++++++++*=X+>+++++++++*=X+++<<[>+++++++++++++++++++>-------------------<<-][>----------------->+++++++++++++++++<<-][>++++>----<<-]>.>.<<<-[+>:=<<X/=<X*=<X<<-=>>X>>[-]++++</=>X>:=<<X>[-]>[-]]<<]<<,]

and with variable names and some messy comments...

DNA# dna encoder

a = input              //get first char
[                      //for each char
    b = 64             //divisor to get first 2 bits
    c = a              //initialize as a
    [                  //while c != 0
        c /= b
        d = 65         //first print char
        e = 84         //second print char
        c              //select c
        [              //if c > 0 (3,2,1)
            d + 19
            e - 19
            c - 1
        ]
        [              //if c > 1 (3,2)
            d - 17
            e + 17
            c - 1
        ]
        [              //if c > 2 (3)
            d + 4
            e - 4
            c - 1
        ]              //c is now 0 (hopefully)
        print d
        print e
        b - 1
        [              //if b is not 1 (last 2 bits)
            b + 1      //reset b
            c = a      //trash top 2 bits (modulus algorithm)
            c /= b
            c *= b
            a -= c
            c = 0      //reset c
            c + 4
            b /= c     //b >> 2
            c = a      //copy a again for next 2 bits
            d = 0      //get a 0 value so we don't loop
        ]
        c              //select c (0 if done with char: exit loop and get next char)
    ]
    a = input          //get next char
]

Decoder

384 bytes - line form

GCGCGCGCGCTAATATATATATTAATTAATTAATTAGCTAATATATTAATTAATTAATTAATTAATTAATTAATTAATTATACGCGCGATTAATTAATTAATGCATGCATGCTATAATATATATATATCGCGGCTAATATATTAATGCATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAATTAGCCGGCTAATATATTAATGCATCGATCGATCGATCGATCGATCGGCCGGCTAATATATTAATGCATTAATTAATTAATTAGCCGATTAATTAATTAATTAATATTACGATGCCGCGATGCGCGCGCGCATATATATATCGGCCGATGCGCATATGCGCCG

99 bytes - symbol form

,,[>>++++[>+++++++++*=X+++<<<-=>>>X[>+<+++++++++++++++++++][>+<------][>+<++++]++++>*=<X<,,>>-]<.<]

var names...

DNA# dna decoder


,
,                  /* read second char into a*/
[                  /* for each set of 4 pairs */
    c = 4          /* loop iterator */
    [
        a - 84     /* if pair was AT (65,84): don't increment b */
        [
            b + 1
            a + 19 /* if pair was TA (84,65): increment b once */
        ]
        [
            b + 1
            a - 6  /* if pair was CG (67,71): increment b twice */
        ]
        [
            b + 1
            a + 4  /* if pair was GC (71,67): increment b three times */
        ]
        a = 4
        b *= a     /* shift b up 2 bits */
        a,,        /* get next char (skip one) */
        c - 1      /* decrement loop iterator: exit loop on 0 */
    ]
    b
    print          /* output b in ASCII */
    a              /* select a (next char) */
]                  /* end if next char is 0 (null terminated string) */

If anyone finds a mistake or is able to run the web interpreter feel free to tell me how wrong I am :P

Answer 3

Python 2, 10216 5152 + 72 98 + 122 110 139 = 10410 10398 5389

Encoder:

import zlib
lambda s:''.join('ACGTTGCA'[ord(c)>>b&3::4]for c in zlib.compress(s)for b in(0,2,4,6))

Decoder:

import zlib
lambda s:zlib.decompress(''.join(chr(int(''.join([str('ACGT'.index(s[i+j]))for j in(6,4,2,0)]),4))for i in xrange(0,len(s),8)))

Answer 4

Javascript (ES6), 6138 6038 bytes

These functions will encode and decode any printable ASCII characters as required by the challenge rules. They are however using a static Huffman code which is optimized for the example text. They should work pretty well on any other English text, as long as there aren't too many capital letters, digits or miscellaneous symbols. But they will perform poorly on a random input.

Edit: saved 94 bytes by rethinking the decoder logic and including all hints provided by Neil

Encoder (305 281 bytes)

s=>(n=0,C={},` e|ahinost|cdlr|.Ibfmuwy|',gpv|"k|;?ATqx|FHW|j|:`.split`|`.map((g,i)=>([...g].map(c=>C[c]=('00'+(n++).toString(2)).slice(-i-3)),n*=2)),s=s.replace(/./g,c=>C[c]||(524160|c.charCodeAt()).toString(2)),s.length&1&&(s+=0),s.replace(/../g,c=>'ATCG'[c=+`0b${c}`]+'TAGC'[c]))

Decoder (391 315 bytes)

s=>(n=N=0,C={},` e|ahinost|cdlr|.Ibfmuwy|',gpv|"k|;?ATqx|FHW|j|:`.split`|`.map((g,i)=>([...g].map(c=>(C[j=i+3]=(C[j]||{}))[n++]=c),n*=2)),s=s.replace(/../g,c=>''+((x='ATCG'.search(c[0]))>>1)+(x&1)),eval(`for(r='';N<s.length-1;){for(i=j=0;!(f=C[j]&&C[j][i])&&j++<19;i+=+s[N++]+i);r+=f||String.fromCharCode(i&127)}`))

DNA sequence (5442 bytes)

Below is the DNA sequence which is generated for the example text.

GCTATAATATCGCGCGTAGCGCATATCGATTAATATTACGGCGCCGTATACGATCGGCGCTAGCATTAGCTAATCGGCATTAGCCGATCGTAATATCGATGCCGATTAATGCATGCTAATGCTAATGCTAATATTAATTAGCCGGCCGATTATATAATCGTAATTAATGCATTAGCATATTACGCGTACGGCCGATATGCATCGATCGCGTAATGCGCCGGCATCGGCCGATTAATATTAGCGCATTACGATGCGCTAATATGCCGCGTATATACGCGGCATCGCGATGCTATAATTATAGCCGATTAGCGCGCATTATAATATTAATGCGCTATACGTAATCGTAATTAGCTAATGCTATAATCGCGATGCGCCGATTAGCATGCGCTACGATGCCGCGATGCCGATGCATTACGCGATATGCGCGCGCTAATGCGCCGATGCATTACGATATATCGGCATTACGATCGGCCGATGCCGTAGCGCTACGATTAATATTACGGCGCCGATCGATGCCGCGATGCCGTAATATCGATGCGCTAGCATTAATCGCGTAGCTACGATGCGCCGCGGCATTAATTAATTAGCGCTACGATTATACGATGCCGCGATTACGGCATTATAATGCCGTACGCGTACGGCTAGCGCCGTAGCATATATTACGCGCGATATGCTAATGCGCCGTAGCGCCGCGATATCGATGCGCTAGCATTACGCGGCGCCGATGCATTACGATATATCGTAGCCGCGGCATCGTAATGCCGCGATATGCGCGCTACGCGCGTATAGCATATCGCGTAATTAATCGCGTAGCTAGCATCGATGCGCCGCGGCTATAATATCGTAATCGATTAATTAGCATATCGTACGTACGCGTACGCGTACGCGATTATACGTAATTAGCATTAATCGTAATCGATTATACGATGCCGCGATTACGGCATTATAATGCCGTACGCGTACGGCTAGCGCCGTAGCATATATCGCGTATATACGCGTAATATGCTAATCGATGCTACGGCCGTACGCGATTAGCTAGCATTAGCATCGATTAATCGTAATATCGATATCGTACGGCATGCATTATAGCCGCGTACGCGTACGCGATTATAATCGTAGCGCTACGTAATTATAATCGCGGCTAATCGATTAATGCATTACGATATATCGTAGCCGGCTAATGCATGCTAATATTAATTAGCCGGCCGATTACGCGCGATTACGGCATTACGGCTAATTAGCATATTACGTAATATCGATATCGGCGCGCATGCCGATGCATATATCGCGTATATACGTAGCGCGCTATAGCCGTAGCGCCGCGATATCGATGCGCTAGCATTACGCGCGATCGCGTATATACGTAGCGCGCCGGCATTATAATCGCGCGTATAATATTATAATGCGCCGATCGTAATTAGCGCTACGGCATGCGCTAGCATTAATTACGGCCGATTAGCGCCGTACGCGCGCGGCCGGCGCTAATATTAGCGCGCCGATGCTACGTACGTACGCGATTAATTACGGCCGATTAATGCATTACGATGCGCATCGATCGCGTATAATCGATGCTACGATCGCGTAGCATGCTATAGCTACGATCGCGTATATAATCGCGATATCGCGTAATTAATCGTAATGCATCGATTACGCGTAATATCGTAGCGCATTAATTACGGCATATCGTACGGCTACGATATCGATCGCGCGATATTAATTATAATCGCGTAGCATCGATGCGCTACGTACGATGCGCTAGCCGATATCGATTAATTAGCCGGCCGATCGCGCGATATTAGCATATTAATTATATAATTAATTAGCCGTAATTACGCGCGATGCTACGATGCCGATTACGATGCGCGCATATGCCGCGATATGCGCGCTATACGATCGCGTATACGATGCCGTAGCGCTAATCGCGATGCTATAATTAGCATATCGTAGCTACGATTAGCCGATCGCGATTACGGCATTAATTAGCGCGCATGCCGTATACGCGCGATCGATTAATCGTAATTACGTAATGCCGGCCGGCATGCCGTACGGCCGATTAATATGCATGCTAATCGCGTACGCGTACGCGGCATCGTACGATGCATTAGCTACGATTAATCGTAATATCGCGTAATATGCTAATCGATGCTAATGCTAATGCTAATATTACGCGCGATCGGCATCGATGCCGATTAATGCGCTAGCGCCGGCGCATCGTACGGCATGCATCGTATAATTAATTATAATCGCGTAATTACGGCATTATAATGCCGTACGCGGCCGGCATTAATTACGGCCGATTAATATTACGGCGCCGATCGATGCCGCGATGCCGTAGCTAATATTAGCGCCGCGCGCGATTATAATCGCGTAATTAATCGCGTAGCATATTAATTATAATGCTAGCATATTAGCGCATCGATGCTATAATTAATCGTAATCGATGCCGATGCCGTACGGCATCGCGATGCCGATCGATGCATCGTAATATCGTACGGCTAATTAGCATGCTAATATCGCGTATAATCGATGCTAGCGCATTAATTAGCTAATTAGCATCGATCGCGTATATAATTAGCATATCGCGTAATTAATCGTAATGCATGCCGCGATATGCTATAATTATACGCGATGCCGTAGCATTATAGCATATGCTAGCATATCGTAGCCGCGTACGTAGCATCGATCGCGTATAATCGATCGGCATTAGCATTACGATCGTAATATGCATGCCGATCGCGTATAATGCCGTAATGCGCCGTAATTATAATCGCGTAATTATACGCGATGCCGATGCGCTAGCCGATTACGCGGCATCGTATAATTACGGCCGATTAATCGGCTATAATGCTAATATGCGCATCGATTACGTAGCCGTATACGCGGCCGTAGCGCATCGATGCCGCGTATATACGCGGCATCGCGATTAATGCATTAATGCATATATTATATAATGCGCCGATTAATATCGATATGCTACGATCGCGTAGCATGCTATAGCTAGCCGCGATATGCTATAATTAGCATATTATAATTAGCATATGCTATATAGCCGATCGTAATATGCGCATTATAATATGCGCGCGCGCTAGCATGCATGCTAATATGCTACGATCGCGTAGCATGCTATAGCTACGATTAATCGCGATTATAATCGCGGCTAATCGATCGGCCGGCTAGCATATTATAGCCGTATACGCGATTAGCGCGCATCGATTAATCGCGATTAATATGCCGTAATTATACGATCGGCGCTAATGCTAGCATATTACGCGATGCCGTAGCGCGCATATATCGCGTATAATGCCGTAATGCGCCGATCGTAATATCGTACGATCGTACGATATTACGGCATTATAATGCCGTACGCGGCCGGCATATCGTATAATATCGTAGCCGATTAATGCATTACGATATGCCGTAATTATAGCTACGGCCGATATCGGCGCATCGGCTAATATGCGCATGCGCCGTAATTATAATCGCGTAATATGCATGCCGGCCGTAGCATCGATCGTACGCGGCATGCGCATGCTACGCGCGGCCGTAGCATCGTAGCGCATCGATTAATGCATTAATGCATATATCGCGTATAATCGATGCGCTAGCCGTACGATCGGCATTACGTACGTAATGCATGCCGCGATATGCGCGCTACGCGCGTAATTACGGCCGCGTATACGCGCGATTATAATCGCGCGTATAATATCGCGTATAATCGATCGGCTAATTACGATCGATGCATGCATCGATTACGTAGCATTATAATCGCGTAATTACGGCGCCGATCGATGCCGCGATGCCGTAATATTAGCGCCGTAATTACGATGCGCCGATTACGGCCGATTACGTAGCATTAATTACGTACGGCCGTAGCATCGATCGCGCGATATATCGTATATATATACGTATAATCGGCTATAATATTACGTAGCCGTAATGCTACGCGCGCGTAATTATATAATATATGCGCTAGCATTACGATGCATATGCATGCCGCGTATAATTAATATGCTATAATATTACGCGTAATATGCATGCGCTAATTAGCATCGTACGTACGCGTACGTAGCGCGCTATAGCGCCGATATATGCTATAATATGCCGATATCGCGATGCGCATCGATCGCGTATATAATCGCGATATGCATGCGCATCGTACGGCTATATAATCGATCGGCATCGATGCCGATCGTAATCGTAATTATAATCGCGTAATTATACGCGATGCATTAATTACGTAGCTAATATTACGCGGCTAATATTAATCGGCGCTAGCCGTAATATCGATATGCGCGCCGTAGCATCGTACGTACGCGTACGCGATTAGCGCGCGCGCGCCGATTATAGCCGATATGCATCGATCGCGTATATACGCGTAATATCGATTACGTACGCGTATAATGCTAATGCTATACGATTAATCGTATAGCCGTAATCGATTAATGCATTAATGCATATATATGCGCGCGCTATACGCGTACGCGATATGCATGCCGATCGCGTATAATCGATGCATTAATTAGCTAATTAGCATCGATGCTAGCCGATGCATGCGCATTAATGCGCGCCGTAATTAGCGCGCGCATCGGCGCTACGATTACGCGTAATATGCTATAATATTAATATGCATGCTAATCGCGTACGCGTACGCGGCTAGCGCCGTAATTAGCGCCGCGGCATTACGATATTAGCGCTACGGCATGCGCTAGCCGTAATTAATTACGGCCGATTACGTAGCCGCGATGCCGTAATGCATGCTAATGCATGCGCGCCGCGATTAGCGCGCATGCCGTAATGCATGCTAATGCTAATATGCGCATCGATGCCGCGTATATACGCGGCATCGCGATCGCGTATAATCGATCGTACGGCATGCATTATAGCCGGCATTAATTAGCGCTACGGCGCATTAGCTATACGATATGCTAGCGCGCTAATTAATTAATATGCGCCGATGCCGGCATATCGTATAGCCGGCGCATCGATCGCGCGATATTATAATCGCGTAATATTAGCGCGCCGGCTACGTACGCGCGATGCGCATATTATAGCCGCGGCGCATCGATCGCGTATAATCGATGCCGATGCCGGCCGTACGCGATGCCGTAGCCGGCATATCGATGCGCTAGCATTATAATCGCGTAATATCGTAGCTAATTAATTAATTACGGCCGATTAATATTACGGCGCCGATCGATGCCGCGATGCCGTAGCTAATATTACGCGGCTAATATCGATTAGCGCATTAGCTACGATTAATCGGCGCTAGCCGTAGCTAATATTACGCGCGATCGGCGCATATGCGCGCCGATCGCGATTAGCATCGGCGCTAGCATGCCGTACGTACGCGTAATTAGCCGGCCGATTATACGATGCCGCGATATGCTATAATATCGTAGCCGTAGCTACGCGCGGCATCGCGTATACGCGCGCGTAGCTAAT

Demo

The snippet below includes some demonstration code.

let e =
s=>(n=0,C={},` e|ahinost|cdlr|.Ibfmuwy|',gpv|"k|;?ATqx|FHW|j|:`.split`|`.map((g,i)=>([...g].map(c=>C[c]=('00'+(n++).toString(2)).slice(-i-3)),n*=2)),s=s.replace(/./g,c=>C[c]||(524160|c.charCodeAt()).toString(2)),s.length&1&&(s+=0),s.replace(/../g,c=>'ATCG'[c=+`0b${c}`]+'TAGC'[c]))

let d =
s=>(n=N=0,C={},` e|ahinost|cdlr|.Ibfmuwy|',gpv|"k|;?ATqx|FHW|j|:`.split`|`.map((g,i)=>([...g].map(c=>(C[j=i+3]=(C[j]||{}))[n++]=c),n*=2)),s=s.replace(/../g,c=>''+((x='ATCG'.search(c[0]))>>1)+(x&1)),eval(`for(r='';N<s.length-1;){for(i=j=0;!(f=C[j]&&C[j][i])&&j++<19;i+=+s[N++]+i);r+=f||String.fromCharCode(i&127)}`))

function encode() {
  var txt, dna;

  if(txt = document.getElementsByTagName('textarea')[0].value) {
    dna = e(txt);
    document.getElementsByTagName('textarea')[0].value = '';
    document.getElementsByTagName('textarea')[1].value = dna;
    document.getElementsByTagName('div')[0].innerHTML = 'DNA length: ' + dna.length + ' (' + (dna.length / txt.length).toFixed(2) + ' nucleotides per character)';
  }
}

function decode() {
  var txt, dna;

  if(dna = document.getElementsByTagName('textarea')[1].value) {
    txt = d(dna);
    document.getElementsByTagName('textarea')[0].value = txt;
    document.getElementsByTagName('textarea')[1].value = '';
    document.getElementsByTagName('div')[0].innerHTML = 'Text length: ' + txt.length;
  }
}

textarea {font-size:10px;font-family:Arial;width:400px;height:70px}

<textarea>I have a friend who's an artist and has sometimes taken a view which I don't agree with very well. He'll hold up a flower and say "look how beautiful it is," and I'll agree. Then he says "I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing," and I think that he's kind of nutty. First of all, the beauty that he sees is available to other people and to me too, I believe. Although I may not be quite as refined aesthetically as he is ... I can appreciate the beauty of a flower. At the same time, I see much more about the flower than he sees. I could imagine the cells in there, the complicated actions inside, which also have a beauty. I mean it's not just beauty at this dimension, at one centimeter; there's also beauty at smaller dimensions, the inner structure, also the processes. The fact that the colors in the flower evolved in order to attract insects to pollinate it is interesting; it means that insects can see the color. It adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic? All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don't understand how it subtracts.</textarea><br>
<button onclick="encode()">Text -> DNA</button><button onclick="decode()">DNA -> Text</button><br><textarea></textarea><div></div>

Answer 5

JavaScript (ES6), 10216 8520 + 85 129 + 97 147 = 10398 8796

Encoder:

s=>s.replace(/..?.?/g,b=>"9876543210".replace(/./g,b=>'ACGT'[b=r>>b*2&3]+'TGCA'[b],r=0,[...b].map(c=>r=r*96+127-c.charCodeAt())))

Decoder:

s=>s.replace(/../g,c=>'ACGT'.search(c[0])).replace(/.{10}/g,b=>String.fromCharCode(...[9216,96,1].map(n=>parseInt(b,4)/n%96^127).filter(n=>n^127)))

Works by packing up to three printable ASCII characters into 20 nucleotides, thus saving 16.6% on average. The characters are mapped from 95 to 1 to shorten the decoder, as it can then use ^127 to floor the division and restore the character code. Excess nucleotides get decoded into 127 which needs to be skipped. The encoder could be 1 byte shorter and the decoder 7 bytes shorter in Firefox 30-57 (note that these are incompatible with the above):

s=>s.replace(/..?.?/g,b=>"9876543210".replace(/./g,b=>'ACGT'[b=r>>b*2&3]+'TGCA'[b],r=0,[...b].map(c=>r=r*96+c.charCodeAt()-31)))

s=>s.replace(/../g,c=>'ACGT'.search(c[0])).replace(/.{10}/g,b=>String.fromCharCode(...(for(n of[9216,96,1])if(n=parseInt(b,4)/n%96|0)n+31)))

Answer 6

Python 3, 15324 + 122 + 211 = 15657 bytes

This is a very wasteful method which converts each character to a three digit number and, for each of those three digits, assigns it a two unit code.

Encoder, 122 bytes

u='AAAATTTCCGTTTTAAAGGCATCGTCGCGGTAGCAGCGCC'
o=''
for i in o.join("%03d"%ord(i)for i in input()):o+=u[int(i)::10]
print(o)

See the encoded version of the example text here

Decoder, 211 bytes

u=['ATAT','ATTA','ATCG','ATGC','TATA','TACG','TAGC','CGCG','CGGC','GCGC']
l=input()
I=u.index
s=''
for j in[l[i:i+12]for i in range(0,len(l),12)]:s+=chr(int(str(I(j[:4]))+str(I(j[4:8]))+str(I(j[-4:]))))
print(s)

Answer 7

Ruby, 97 + 96 + 5152 = 5345 bytes

Encoder program requires the flags -nrzlib.

Zlib::Deflate.deflate($_).bytes{|b|('%04s'%b.to_s(4)).chars{|c|$><<"ATTACGGC"[2*c.to_i,2]}}

Decoder program requires the flags -przlib.

gsub(/../){"ATTACGGC".index($&)/2}
gsub(/..../){$&.to_i(4).chr}
$_=Zlib::Inflate.inflate$_

Answer 8

Python 2, 12770 + 204 + 271 = 13245

Encoder:

from itertools import*
D=[''.join(p)for p in permutations('AT TA CG GC'.split())]
e=lambda x:''.join('AT'+D[c-32]if c<56else'TA'+D[c-56]if c<80else'CG'+D[c-80]if c<104else'GC'+D[c-104]for c in map(ord,x))

Decoder:

from itertools import*
D=[''.join(p)for p in permutations('AT TA CG GC'.split())]
n=D.index
d=lambda x:''.join(chr(n(c[2:])+32)if'AT'==c[:2]else chr(n(c[2:])+56)if'TA'==c[:2]else chr(n(c[2:])+80)if'CG'==c[:2]else chr(n(c[2:])+104)for c in map(''.join,zip(*[iter(x)]*10)))

Every character is encoded to a 10-character (5 unit) string, with the first unit indicating what quarter of the printable character string it belongs to, and the last four indicating what character in that quarter is represented.

Try it here.

Answer 9

PHP, 5106 + 297 + 161 = 5564

encoder

$t=str_replace("=","",base64_encode((gzdeflate($_GET["e"]))));$c="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";$e=["AT","TA","CG","GC"];$n="";foreach(str_split($t)as$b){$p=str_pad(base_convert(strpos($c,$b),10,4),3,"0",STR_PAD_LEFT);$n.=$e[$p[0]].$e[$p[1]].$e[$p[2]];}echo $n;

decoder

$e=["AT"=>0,"TA"=>1,"CG"=>2,"GC"=>3];$a=str_split(strtr($_GET["d"],$e),3);$o="";foreach($a as $v)$o.=$c[base_convert($v,4,10)];echo gzinflate(base64_decode($o));

Answer 10

Node.js (5.6.0), 5104 + 125 + 122 = 5351

I was originally working in JavaScript, but Node.js provides compression much more easily. Thanks Neil for helping trim out 5 bytes on the encoder!

Encoder (125 bytes):

s=>[...require('zlib').deflateRawSync(s)].map(a=>('000'+a.toString(4)).slice(-4).replace(/./g,b=>'ATCG'[b]+'TAGC'[b])).join``

Decoder (122 bytes):

s=>require('zlib').inflateRawSync(Buffer(s.replace(/../g,a=>'ATCG'.search(a[0])).match(/..../g).map(a=>parseInt(a,4))))+''

DNA Sequence (5104 bytes):

TATATATATATATAATGCATCGTACGATGCCGGCTACGGCATGCATATATATGCATGCGCGCTAATTATATATACGATCGATCGGCCGTAGCATGCATATCGTAGCGCATCGATATATTACGTAGCTAGCATATGCCGCGATATCGTATAGCCGCGATCGCGGCCGTAATATGCGCGCTAATATCGGCATGCTACGATCGATGCATGCCGGCATTAATTACGCGTATACGTATAGCTAATTAATTATAATCGCGCGATTAGCCGGCGCGCGCTAGCGCTAATTAGCGCCGCGTATATAGCCGATCGTATACGTAATCGGCATTAATATCGATCGTAGCATCGGCTATACGGCTAATCGATGCGCCGTATAATTAATTATAATGCCGGCCGATATGCATGCATATTATACGGCCGCGCGTATAATGCATCGATTAGCCGTACGCGTAATTAGCTATACGTAATCGTACGTAGCCGCGTATACGTAATATATCGCGTAATTATAATCGATCGGCTACGCGCGGCGCCGATATGCTAGCATCGATCGTAATATGCTAATCGTATACGTATATACGTACGCGATCGGCATGCATGCATCGCGGCTATACGTACGGCCGATATGCATTAGCATATCGTAGCTAATCGATGCGCCGGCGCATATCGATCGATGCGCTAATATGCCGATTAATGCCGTAGCTATACGCGATCGTATAATGCGCGCATCGATGCATGCCGTAATTACGCGGCTACGATTACGCGTACGATGCTATAGCTACGCGTAATTAATTAGCTAGCATCGGCCGATTACGGCCGCGGCTACGTAGCATGCTAATCGCGTAATTATAGCGCCGGCGCATGCTAGCATGCTAATCGCGATGCTAATTAATCGTAATTACGCGCGCGCGTAATCGGCCGCGATGCCGCGTATAATTACGTAATGCCGTATAGCTAATCGATGCCGCGTACGCGGCGCTACGATGCCGCGATATCGCGTACGATCGTAGCTAGCATATTAATATTATAGCCGGCCGCGTAGCATGCATCGCGATTATATACGCGCGGCGCATGCTATAATTAATTAATGCTAATTAATCGCGATGCCGCGCGGCCGATTACGCGCGTAGCCGTATACGTAGCATCGGCGCATCGGCCGCGTAGCTATAATGCGCCGGCTAATCGGCTACGGCATATTAATGCCGCGATCGATCGTACGGCGCTATAATGCCGGCCGCGTAGCCGCGTATAATTAATGCCGATTAATCGCGGCGCTATATAATATATTATAGCGCGCATTATATAGCGCCGATGCTAGCGCTATACGGCGCTACGTAATTATAATATTATATAGCATGCTAGCCGCGATTATAGCATCGATGCTAATGCTACGCGCGCGTACGCGGCTACGATTAATTAGCTAATCGATATATGCTACGATTATATACGGCCGTAATTACGCGCGTAGCCGCGTAATGCCGTAGCATATCGTACGATATATTATACGGCGCTAATTACGCGATCGCGCGATTACGATCGTAGCATTAGCCGTAATTAATATATTATAGCATTAGCATTACGCGATCGCGGCATCGCGCGTAATGCTATAGCATCGCGGCTATAGCCGTAGCTATATAATGCATGCCGGCGCTAGCTAGCGCATATATTACGGCATATGCATTAGCGCATGCCGATATGCTACGATATCGGCTAGCCGATCGTATACGCGATCGGCCGCGTATAATCGCGCGGCGCTACGTATAGCTACGCGCGTAATTATAGCGCCGGCATTACGCGATATATGCCGTAGCATGCCGGCCGCGATTAGCCGCGTAATATATATTACGCGTAGCTAGCTAATTACGGCTACGGCTATAGCCGGCCGATTATAATTAATATTACGGCCGCGGCTATAGCATATATATGCGCATGCATTACGATTATATAGCATGCATATATCGATATCGTAATCGATTATAATATTATACGATCGCGCGATTACGATTATATACGTATAGCATATTAGCTACGTATAGCATTATAGCATATATGCTAGCTAGCCGGCTAATTAATATATGCCGCGATATATATGCGCATTAGCATGCCGATCGCGTAGCGCATCGATTAGCATATCGGCATGCGCGCCGTAATGCTAATGCTATATAATCGCGCGGCGCGCCGGCCGGCGCCGGCATATGCATATATATGCCGGCATGCATGCCGATTATATAGCGCGCCGCGTATATAGCCGCGATGCCGGCATTAGCATCGGCATCGCGGCTAGCGCATCGATCGTACGTACGTATAATTAGCATATCGCGCGCGGCATGCCGCGATTACGTAGCTAGCATTAATATATATCGATTAGCGCATGCTAATATATGCCGATATATATATTATAGCCGATCGGCGCATTATAGCCGATTAATTAATCGCGATTACGTACGGCATTATATACGTATACGCGCGTATAGCGCATATATTAATATCGATATGCGCGCATTATATATAGCCGATTACGTAATGCCGGCGCCGCGATGCATTAATCGATGCTAATATATTATACGTAATATCGGCTACGCGTATAGCATATATTACGCGATTACGATCGGCGCGCGCGCATGCTAGCATATCGATGCGCGCCGTAGCCGATCGCGCGGCATTAGCATGCGCTATAATCGATATATATTAGCCGATCGTATACGGCTACGCGCGTAATGCATTAGCCGTAGCATGCCGATTATAGCATATCGCGGCGCATATCGCGGCTACGGCATTAATCGATTATAATCGATGCATTAGCGCCGTAATGCCGATCGATTAGCATCGCGGCTATACGATCGGCTATAGCATTAATATATATTATACGCGGCATATATTAGCGCATTAGCTACGTAATATGCGCCGATTATACGGCCGGCATGCGCTACGGCATATTAGCCGCGTAATCGTACGCGATATTACGCGCGTAATGCCGTAGCGCATCGGCATATATCGCGATGCTACGTAATGCATGCATGCTAATCGATGCCGCGATCGATGCGCTAGCATCGTATAATATCGGCTAATCGTATACGTATATATAGCGCGCTATACGTAATGCCGGCTATATACGGCCGGCGCATGCGCATATGCATCGGCTAATTACGCGATCGTACGATCGATATATGCTACGGCGCGCATATCGGCTAGCCGCGCGCGGCCGGCTAATGCCGCGCGATATCGGCGCTATACGGCCGTACGATGCCGCGCGATATCGATGCTATAATTACGCGTAATCGATATGCGCTAGCGCCGATCGTATAGCTACGTAGCGCATTACGGCATGCTACGCGGCATGCATTAATCGGCCGATCGGCGCCGTAGCTACGATATCGTACGGCGCCGGCGCATTAGCTAGCGCGCGCGCCGCGGCATGCTATAATATTACGTACGCGTACGTAATATTAGCATGCATTAATTAGCCGGCATTATAGCTACGCGTACGCGATGCATTATACGTAGCGCTAGCATCGCGCGCGCGTATATAATGCCGCGTATACGATTAGCTATAGCCGGCCGCGCGGCTAGCATGCCGATCGATGCTAATCGGCCGTAATTACGATATTATATATATATATAGCTAGCGCATGCCGTACGGCCGTACGGCATATATTAATTAATTATAGCGCTAGCTACGATTATAGCTATATAGCTACGTAATCGCGGCATCGTAATCGGCGCTAGCCGCGATGCTAGCCGATCGCGGCCGGCCGCGTAATATGCCGGCGCCGTAATGCCGATCGTATATACGGCATCGCGGCCGCGATGCATGCCGATATCGTACGCGATATCGCGGCTATAGCCGATATCGTATACGCGTAATGCGCATGCTACGATATGCCGCGCGTATATAGCCGATCGGCCGCGTAATATTATAATCGGCATGCATATGCGCCGCGCGTACGGCGCTAATATCGCGCGATTAATTAATATATATTAGCATCGCGATGCGCATTATAATGCTACGCGGCGCCGGCGCCGATCGTATATAATGCCGGCCGCGATATATTAGCTATACGCGCGCGCGGCGCGCTACGCGTATAGCGCGCATATCGATATTAGCATGCTAATCGTAGCATGCATATCGTATACGCGCGATGCGCCGCGATGCATCGGCGCGCGCATGCCGGCGCGCGCCGCGCGGCATTATACGTAATCGTAGCGCGCGCCGATATGCTAATTAGCGCCGCGTAGCATGCTACGGCCGCGGCCGGCCGGCGCGCCGCGGCGCATATCGCGGCATCGCGGCTAATATCGCGATGCCGCGCGGCGCCGATCGTAGCTAGCTAGCGCGCATCGATATATATGCGCGCATGCCGCGTAGCTAGCGCATCGTAATTATAGCATCGCGCGCGGCATCGCGGCGCGCGCTAATTACGTAGCGCTACGCGATTACGCGATTAATGCGCGCCGGCATCGGCATTAGCGCATGCATTATATATATACGCGCGTACGGCGCTACGATATCGCGGCTATAATATGCTAGCGCCGCGATATATCGGCGCATCGTAATATGCGCTAATATATTAGCGCTAATATGCATCGGCATCGATCGGCTACGTATAATATGCGCGCGCATATATCGATATTAGCCGCGTACGTATACGTACGTATATAATGCTAATGCGCATTATAGCCGATTACGTACGATATGCGCGCATTAATCGTATATAGCTATACGATCGCGGCTATACGATATGCTAGCCGTATAGCGCTAGCATATATTAATATCGGCATATGCTAGCGCCGGCCGCGGCTATATACGGCATGCGCGCTACGGCGCTACGCGCGGCGCGCCGTATAATTATACGCGTAGCCGGCGCATATATCGGCCGTAGCCGGCATATGCGCATCGGCGCTAGCTATAGCTAATGCGCTAGCTACGTATACGTAGCCGTAATGCGCCGATGCGCATTAGCATGCTAGCCGCGCGTATACGTACGTATACGATCGCGCGGCGCTATACGCGGCGCCGTACGATGCGCGCCGATATGCATATCGATATATCGGCATGCGCTATACGTAGCATGCATGCATGCTATACGTACGATGCGCGCGCGCGCATATATTA