Genome:
Adagio and Scherzo
for orchestra
performance time: ~12:00
preview score below:
Program Notes
The most important scientific discoveries of the dawning century
will no doubt be related to our increased understanding of
the human genome. Although 50 years have passed since the
discovery of the physical structure of DNA, the complete map
of the human genome was completed only a few short years ago.
DNA, or deoxyribonucleic acid, is a molecule, but a fantastically
complex one. It is bundled together into 46 individual groups,
called chromosomes, and packed into the nucleus of nearly
every one of your 10 thousand trillion cells. Each cell contains
nearly 6 feet of DNA, which means that the average adult is
carrying around more than 12.4 million miles of genetic material.
That’s enough to circle the earth 500 times at the equator.
This amazing substance is the written code for building
life. Using an alphabet of only four letters, DNA is a coded
digital recipe for building proteins. The same alphabet and
syntax are shared by all living things. Each of the four letters,
called nucleotide bases, is read together in three-letter
words called codons. Each codon stands for one of 20 amino
acids. These amino acids are combined to create even more
complex proteins, and all living things are made of proteins.
If the genome is a book, chromosomes are chapters, individual
genes are paragraphs, codons are words, and nucleotide bases
are letters.
When a complete copy of the human genome was mapped in 2000,
I became fascinated with using this data as source material
in a musical composition. The virtually limitless supply of
non-random data is perfectly suited to providing source material
for composition. The fact that these data represent the code
for life itself appeals to the artist as well as the scientist.
This first step was to devise a system to convert DNA into
musical pitches. A four-letter alphabet is not sufficient
for each nucleotide base to represent a pitch. Conversely,
the 20 amino acids are too many for each to represent a pitch.
The solution lies in the fact that some amino acids are used
more frequently than others. The 12 most-common amino acids
were arranged in a series and each assigned a musical pitch,
and the 8 least-common acids were arranged in a second, incomplete
pitch series. The 4 most common acids in series one were reserved
for the 4 pitches that are not accessed by the incomplete
second series. (See table below). By this method, each of
the 20 amino acids has similar odds of selecting one of the
12 musical pitches.
The next step was to download random sections of the human
genome, and derive long chains of pitches. I started at random
points on each chromosome, encoding musical pitches until
enough thematic material existed for a composition of substantial
scale. Because much of the material was too random to make
melodic sense, I ended up encoding about four times more sequences
than needed. Allowing myself the freedom to pick and choose
good data, I was able to use sequences that naturally implied
a harmonic structure. Once the basic themes were decided upon,
even more genetic material was encoded for use as small musical
interjections, counterpoints, and other musical effects. Although
the music was composed freely after this point, a strong preference
was reserved for material that was derived directly. At several
points during the composition process, I went back for more
data when it became clear that melodic entrance of a certain
shape or character was needed.
Table of Codon to Pitch Conversion
|
|
Codon |
Amino Acid |
Pitch Series |
Pitch |
|
GCA |
Alanine |
1 |
A |
|
GCC |
Alanine |
1 |
A |
|
GCG |
Alanine |
1 |
A |
|
GCT |
Alanine |
1 |
A |
|
AGA |
Arginine |
1 |
B |
|
AGG |
Arginine |
1 |
B |
|
CGA |
Arginine |
1 |
B |
|
CGC |
Arginine |
1 |
B |
|
CGG |
Arginine |
1 |
B |
|
CGT |
Arginine |
1 |
B |
|
AAC |
Asparagine |
2 |
G |
|
AAT |
Asparagine |
2 |
G |
|
GAC |
Aspartic acid |
2 |
A |
|
GAT |
Aspartic acid |
2 |
A |
|
TGC |
Cysteine |
2 |
B |
|
TGT |
Cysteine |
2 |
B |
|
GAA |
Glutamic acid |
2 |
B |
|
GAG |
Glutamic acid |
2 |
B |
|
CAA |
Glutamine |
1 |
B |
|
CAG |
Glutamine |
1 |
B |
|
GGA |
Glycine |
1 |
C |
|
GGC |
Glycine |
1 |
C |
|
GGG |
Glycine |
1 |
C |
|
GGT |
Glycine |
1 |
C |
|
CAC |
Histidine |
1 |
D |
|
CAT |
Histidine |
1 |
D |
|
ATA |
Isoleucine |
1 |
D |
|
ATC |
Isoleucine |
1 |
D |
|
ATT |
Isoleucine |
1 |
D |
|
CTA |
Leucine |
1 |
E |
|
CTC |
Leucine |
1 |
E |
|
CTG |
Leucine |
1 |
E |
|
CTT |
Leucine |
1 |
E |
|
TTA |
Leucine |
1 |
E |
|
TTG |
Leucine |
1 |
E |
|
AAA |
Lysine |
1 |
E |
|
AAG |
Lysine |
2 |
E |
|
ATG |
Methionine* |
2 |
C |
|
TTC |
Phenylalanine |
2 |
D |
|
TTT |
Phenylalanine |
2 |
D |
|
CCA |
Proline |
1 |
F |
|
CCC |
Proline |
1 |
F |
|
CCG |
Proline |
1 |
F |
|
CCT |
Proline |
1 |
F |
|
AGC |
Serine |
1 |
G |
|
AGT |
Serine |
1 |
G |
|
TCA |
Serine |
1 |
G |
|
TCC |
Serine |
1 |
G |
|
TCG |
Serine |
1 |
G |
|
TCT |
Serine |
1 |
G |
|
ACA |
Threonine |
1 |
G |
|
ACC |
Threonine |
1 |
G |
|
ACG |
Threonine |
1 |
G |
|
ACT |
Threonine |
1 |
G |
|
TGG |
Tryptophan |
2 |
E |
|
TAC |
Tyrosine |
2 |
F |
|
TAT |
Tyrosine |
2 |
F |
|
GTA |
Valine |
1 |
A |
|
GTC |
Valine |
1 |
A |
|
GTG |
Valine |
1 |
A |
|
GTT |
Valine |
1 |
A |
|
TAA |
STOP |
x |
x |
|
TAG |
STOP |
x |
x |
|
TGA |
STOP |
x |
x |
|
* When within a sequence.
When ATG is at the start of a gene, it means "begin encoding."
|
