If you have ever listened to Pandora Internet Radio, you know that this radio service plays musical selections for you based on your own musical interests (a skill that’s honed the more you use their services). You provide the feedback by pressing the “thumbs up” or “thumbs down” button after each track, and by magic, the next piece you hear is pretty much what you wanted to hear. It’s very cool, indeed, but it poses a question: How do they achieve this? It almost seems like sorcery. After all, music is a highly subjective experience.
Pandora’s team consists of trained musicologists who listen to every piece in the catalog and break it down into 450 attributes and musical characteristics. When you give them your feedback about your musical preferences, the program chooses the next song with similar “chromosomes.” In fact, Pandora started as a “Music Genome Project” which was conceived in late 1999, in an effort to “capture the essence of music at the fundamental level.”
This scientific dissection is nothing new in the field of musicology. Researchers in London have tried to crack the code, which determines why some tunes, known as “earworms”, get stuck in our head. By analyzing common characteristics of these tunes, they found that the stickiness of earworms results from a balance of certain musical intervals and rhythmic structures. “By studying earworms” – says the program’s co-director Daniel Mullensiefen – “we really can decode the DNA of a pop song that perfectly lodges in our memory.” In this way, they are able to predict with 70 to 80 percent accuracy which tunes will become popular.
While musicians have been busy decoding music’s DNA, scientists have been busy doing the opposite –assigning musical notes to the strands of DNA.
DNA, or deoxyribonucleic acid, is a record of genetic information written in a chemical language. It is composed of long strings of molecules called nucleotides, which contain chemicals called bases. There are four bases, commonly abbreviated as A,C,G and T, adenine, cytosine, guanine, and thymine. They form pairs called base pairs. Each base pair makes one “rung’ of the DNA ladder called a Double Helix. Genes are written in a code using the four bases, A, C, G and T, which come in groups of three. A group of 3 base pairs is called a codon. Codons tell a cell what amino acids to build. There are 20 amino acids and they are the building blocks of proteins.
The human genome has a sequence of 3.2 billion base pairs. These base pairs could fill 200 telephone directories and if read aloud, would take 50 years to read. If you took all the DNA from a single human cell, stretched it out and joined it together, it would be about 2meters (6ft) long. If you put the entire DNA in your body end to end, it would reach from the Earth to the Sun and back 600 times. So, how does one go about creating DNA music?
One of the pioneers in the DNA music field is David Deamer, professor of Chemistry and Biochemistry at the University of California, Santa Cruz. In 1988 he collaborated with Susan Alexjander, composer and music theorist, on a science/art project to collect frequencies from the bases of DNA with a spectrophotometer. The spectrophotometer is an analytical instrument that measures the intensity of light as a function of its wavelength. Deamer passed infrared light through a base molecule of DNA, and when the light was absorbed at specific frequencies, the instrument plotted the absorption bands as a spectrum with a wavenumber (number of waves per centimeter).
Once the wavenumber was determined, it was converted to hertz (Hz). In order to get frequencies within hearing range, the authors translated the patterns of ratios in light into a sound medium,in order to “hear’ the information. The data was programmed into a Yamaha DX7 IID synthesizer, which created sound banks from the hertz numbers. The resulting music was microtonal (microtones are smaller than half-tones on a piano).
This collaboration was a result of Susan Alexjander’s bid to answer the questions she had posed to David Deamer – “Is our biology harmonically ordered in any way? If we could hear the body, delve into its rhythms and frequencies, what might it sound like?”
This project was unique in that instead of assigning arbitrary pitches to bases, amino acids, or proteins, the actual vibrational frequencies were collected directly from the molecules. These frequencies were used as the basis for the musical composition –“Sequencia”, performed by voice, violin, cello, tabla, and synthesizer.
In 1986, Susumu Ohno, a geneticist and molecular biologist, known for his work in genetic sex determination and evolution through gene duplication, also turned DNA sequences into musical pieces. He notated more than fifteen songs based on the DNA of a variety of living organisms. Ohno assigned musical notes to the four bases – *do* to cytosine, *re* and *mi* to adenine, *fa* and *so* to guanine, and *la* and *ti* to thymine. He also chose a particular duration for each note and ordered the nucleotides according to their molecular weight. His design was based on the principle of repetition recurrence found in nature and in genome duplication.
Ohno and his wife, Midori, a musician, used their coding assignment to reverse the process. They translated the Chopin Nocturne Op.55 No1 into a DNA sequence and what they found was astounding – the resulting DNA was similar to the large subunit of the mouse DNA polymerase II, differing only by one nucleotide (someone should try to convert the musical portraits of the animals from the *Carnival of the Animals* by Saint-Saëns into a DNA sequence to see if there are any similarities).
When you listen to DNA music, you wonder – how can these compositions be faithful to a precise genetic sequence and at the same time sound like real music? Not all conversions of DNA sequences into sounds can be called music. Some are just the acoustic signatures of different species of organisms. Nevertheless, they are fascinating to listen to not only because they share with us a secret of the organism’s hidden life at a cellular level, but also because we are able to hear the dynamic force of life itself.
There are so many creative ways in which DNA sequences can be translated into music. Twenty amino acids can be grouped according to their hydrophobicity, acidity, and polarity – according to John Dunn, a computer programmer and a creator of Algorithmic Arts. Together with K.W. Bridges, a botanist, Dunn created software that converts protein sequences into music. They adjusted the instrumentation and tempo to match the biological characteristics of the protein of different organisms, such as starfish and sea urchins.
If you are interested in delving deeper into this and creating DNA music yourself, check out John Dunn’s website. His program allows composers to map nucleotides and amino acids in a musical grid. Composers can assign pitches, rhythms, and instruments to the amino acids or nucleotides and hear the DNA sequence played back through the computer’s MIDI player.
Converting DNA into music can be done by many different computer programs. One of them is ProteinMusic (PM) developed by Ross King, a biologist from the University of Wales in Aberystwyth (U.K), and Colin Angus, a musician. They hope that when using the program, “users could feed in their own DNA sequences and develop their own anthems.”
Scientists have been fascinated by music since the time of Pythagoras, who, in the sixth century BC, declared that “there is music in the spacings of the spheres.” Many scientists are accomplished musicians – William Herschel, Albert Einstein, Ilya Prigogine, Saul Perlmutter, and Brian Cox are few examples. But the real question is – apart from the pleasure derived from listening to one’s own DNA, what scientific value has all this? Could any scientific truths be revealed by hearing DNA patterns?
It’s hard to tell at this stage if scientists, who research the connections between musical and DNA patterns, will make new discoveries. But one thing comes to mind: if (or when) we encounter intelligent life from other planets, could we play the symphonies of our DNA to communicate with them? This way, we might be able to transcend the interstellar language barrier.
Even if this whole exercise proves to be unproductive from the scientific point of view, there is always poetic and philosophical value in listening to one’s own “body music.” The Scottish philosopher Thomas Carlyle reminded us long before DNA was discovered “See deep enough and you see musically.”
Read their paper, “The Infrared Frequencies of DNA Bases: Science and Art,” here.