Melody, rhythm, Super Evolution, drums, tape — and their parallels in the literature
FASTAplayer does not turn a single DNA string into a single stream of notes. It is a small orchestra of genetic readers. Each instrument looks at DNA at a different grain — codon, amino acid, or single nucleotide — and each has its own genetic table. Playback is the moment those tables speak at once against a shared clock.
Four ideas hold the system together:
A melody FASTA chooses pitches. A separate rhythm FASTA chooses durations. They can come from different files, loop independently, and be reversed or complemented on their own.
The 64 DNA codons are a lookup table, not a hard-wired score. Scale presets, rhythm presets, and Super Evolution remap those tables while the DNA itself stays the same.
Super Evolution is a third DNA stream. It does not rewrite the melody sequence. It changes the scale and chord that the melody table is currently using.
Synth and sampler read codons. The drum machine translates those codons into amino acids. The tape deck reads one base at a time. Same molecule, three alphabets.
FASTAplayer splits what most earlier DNA-music tools kept in one mapping: which pitch versus how long it lasts. That split is biological as well as musical. A coding sequence is a string of triplets (codons). FASTAplayer reads melody and rhythm as two such strings, advanced together during playback, but looked up in two different tables.
The melody FASTA is chopped into non-overlapping three-letter codons (AAA … TTT). Each codon is looked up in the Melody Genetic Table, which assigns a pitch (for example C4, F#5) or a rest. AAA is reserved as a pause. The other 63 slots are filled from the current scale or chord — Chromatic, Major, a pentatonic, an imported .scl file — and can be edited codon by codon.
What you hear from the synthesizer and the sampler is that table after the usual performance transforms: transpose, octave range folding, and (if Super Evolution is on) the live scale/chord. The compact playback display therefore shows three related names: the codon, the table note, and the sounding synth or sampler note.
The rhythm FASTA is a second codon stream. The Rhythm Genetic Table maps each codon to a duration. Under the current reference codec, the Standard Set, those durations are fractions of a quarter note. TTT is not a length: it is the chord marker (duration 0), so several melody notes can attack together. Other rhythm presets exist for looser, more “genetic” feels; MIDI import and export always use Standard Set so a round-trip stays faithful.
The synthesizer, sampler, and tape deck all take their note or sample lengths from this shared table. Change a codon’s duration, and all three instruments move together. The drum machine is the exception: it keeps its own built-in duration table (a legacy-style mapping) and its own tempo/swing.
Ordinary Evolution in FASTAplayer morphs synthesizer parameters (filters, envelopes, effects) along a DNA-driven path. Super Evolution is different. It is a third DNA sequence whose job is to change the harmonic world the melody is currently being read in — root, duration of that state, and scale or chord — while playback continues.
Super Evolution walks its FASTA in groups of nine bases (three codons). Each group is translated by three specialized tables:
First codon → a chromatic pitch from C2 to D7, or a pause. This is the key centre the melody table is folded around.
Second codon → how long that harmonic state lasts, from tiny fractions of a beat up to multi-bar holds.
Third codon → which scale or chord type fills the melody genetic table (Major, Dorian, a triad, an imported Scala scale, and so on).
When the cursor advances to the next triplet, the melody genetic table is rebuilt for the new scale/chord and root. The melody DNA does not change; only its translation does. That is the same logic as reading a gene in a new frame or with a new codon table: the letters stay, the protein (here: the pitch set) changes.
Cadence plasmids are Super Evolution sequences written as musical progressions — prepared 9-base words that move through related scales and chords rather than jumping at random. Reverse and complementary transforms apply to this stream as well, so a cadence can be mirrored or Watson–Crick inverted. Cursor speed stays in step with the main tempo, and the Super Evolution loop is independent of the melody/rhythm loops.
The drum machine is FASTAplayer’s percussion reader, and it uses the biological genetic code rather than a musical one. DNA is translated codon → amino acid (the standard 20-letter protein alphabet, plus stop), and each residue triggers a pad. A kit is therefore a set of 20 sounds, one per amino acid, whether those sounds are spectroscopic “molecular drums,” a silver acoustic kit, or tabla.
The default kit is not a conventional drum library. It is built from vibrational spectroscopy of the amino acids themselves (infrared and Raman normal modes), transposed down into the audible band while keeping relative spacings. Side chains leave a fingerprint: aromatics (Phe, Tyr, Trp) tend toward denser, ring-like spectra; charged residues (Asp, Glu, Lys, Arg) add sharper components. The result is a 20-voice kit in which each pad is a sonified molecule, not an arbitrary sample assignment.
The tape deck is the coarsest genetic reader: it does not wait for a codon. It advances one nucleotide at a time — A, T, C, or G — and each base is a channel with its own long sample. Defaults load immediately (rain on A, fire on T, birds on C, waterfall on G), and any channel can be replaced from the built-in ambience library or a file you upload.
Duration, however, is still codon-timed. The tape deck looks at the rhythm sequence for how long the current base’s sample should run, then crossfades toward the next nucleotide. Identity is nucleotidic; length is codon-rhythmic. That hybrid is what keeps tape beds locked to the same grid as the synth and sampler without forcing atmosphere samples onto a 64-codon table they do not need.
On top of the mapping sit analog-style treatments: saturation and compression, tape delay (optionally tempo-synced), reverb, and automatic gain so recordings of very different levels sit together. Custom samples travel with patches as a ZIP, so a “tape piece” is a DNA trigger map plus the four (or fewer) files it plays.
FASTAplayer is an implementation, not a claim of historical firsts. The pieces below are the methods it most clearly rhymes with. Citations are collected at the end of this page and discussed at more length in DNA Sonification.
Hayashi and Munakata’s 1984 letter in Nature established that nucleotides can be assigned notes by an explicit table. Ohno and Ohno argued that genomic repetition is already a compositional principle. Later software treated proteins as the unit: King and Angus’s Protein Music (1996) and Takahashi and Miller’s Gene2Music (2007) map residues onto reduced pitch alphabets. Kramer and colleagues (2017) surveyed sonification algorithms that range from one note per base to codon parsing in multiple reading frames — exactly the spread FASTAplayer uses across tape (base), melody/rhythm (codon), and drums (residue).
Keeping pitch and duration in two codon tables is FASTAplayer’s practical extension of that literature: one genetic code for an amino-acid-like pitch alphabet, another for time, so MIDI round-trips and live scale changes do not fight each other.
Reginald Bain’s Genetic Variations treats mutation as a musical operation on a sequence. Eduardo Reck Miranda’s GeMS goes further and maps transcription, translation, and folding onto changing musical parameters (Miranda, 2020). Super Evolution sits closer to Miranda than to a simple mutate-the-FASTA effect: the melody DNA is held constant while its translation table — scale, chord, root — is rewritten on a DNA clock. Ohno’s “repetitious recurrence” is audible here as cadence plasmids: short, repeating 9-base words that function like harmonic ostinatos.
Miranda’s Artibiotics work, which couples synthetic biology with composition, is also the nearest published analogue to FASTAplayer’s interest in prospecting “music peptides” and “music proteins” as candidate therapeutics. Super Evolution supplies the moving harmonic context in which such sequences can be heard as more than a static codon-to-note list.
Susan Alexjander and David Deamer’s Sequencia (1990) already turned infrared frequencies of DNA bases into a microtonal scale. Markus J. Buehler’s later programme translates amino-acid vibrational spectra into musical material and uses that representation in protein and materials design. FASTAplayer’s default drum kit is in that spectroscopic line: IR/Raman modes of the twenty residues, transposed into drum range, triggered by the real genetic code. King & Angus and Gene2Music remain the software ancestors for “one instrument voice per amino acid.”
Public-engagement sonifications that assign one pitch per base (as in the simple mappings discussed by Smith et al., 2021) are the conceptual parents of the tape deck’s A/T/C/G channels. FASTAplayer replaces the pitched beep with long field recordings and then times them from the rhythm codon table — a combination of the earliest nucleotide maps with the later, more structured codon algorithms in the ICAD / Kramer survey. The tape metaphor itself is compositional, not biological: saturation, delay, and crossfade are how those four beds become a continuous environment instead of four one-shots.
A fuller historical narrative, including Middleton’s Musicalgorithms, Pajak’s Sounds of HIV, and Cooper’s Chromos, is on the DNA Sonification references page. For knobs, plasmids, and patch files, use the user manual.