discovery of DNA was one of the great triumphs of science. But ever
since this discovery there has been a strange trend which we may call
“DNA inflation,” “DNA exaggeration,” or even “DNA
apotheosis.” The trend has been to carelessly describe DNA in ever
more grandiose terms, regardless of the actual facts. A particularly
absurd and careless example of such talk is found on page 31 of the
book “Super Genes” by Deepak Chopra and Rudolph E. Tanzi. The
authors write the following:
as the “brain” of the cell, is ultimately in charge of every
process...The DNA that's neatly tucked inside each cell is something
magnificent, a complex combination of chemicals and proteins that
holds the entire past, present, and future of all life on our planet.
is almost completely inaccurate. DNA is nothing like a brain, and is
not even like a computer. DNA is not a “combination
of chemicals and proteins,” because it does not contain a single
protein. Instead DNA contains chemical information used by the body
when it makes proteins. And DNA does not contain “the
entire past, present, and future of all life on our planet.”
statement this outrageous is not very common, but it is very common
for writers to inaccurately describe DNA. One very common claim is
that DNA is a blueprint that lays out the complete specification of
the human body. Another common claim is that DNA is a recipe (or a
library of recipes) for making an organism. It is also sometimes
claimed that DNA is like a computer program for generating our
such statements are not warranted by the facts. Judging from the
facts, we must conclude that while DNA uses a code of symbolic
representations (the genetic code), DNA is not a blueprint for making
a human, is not a recipe for making a human, and is not a program or
algorithm for making a human. The facts indicate the DNA is not
anything close to a complete specification of an organism, but that
DNA is instead something much simpler, mainly just a kind of database
used in making particular parts of an organism.
are 6 reasons for thinking that DNA is neither a blueprint nor a
recipe nor a program for making human beings.
#1: The “language” used by DNA is a minimal feature-poor language
lacking any grammar or capability for expressing anything like a
blueprint, a recipe, a program or an algorithm for making a human
First, let's look at
the different ways of specifying a three-dimensional object, and then
look at whether any such way could be used by using DNA.
are two ways in which you can create a specification for building
something that will exist as a three-dimensional object. The first
way is the blueprint approach, in which you don't specify the steps
that must be taken to create the object, but merely specify how the
object will look once it is constructed. You can create a kind of
blueprint by creating a drawing or image that will specify how the
completed object should look. Alternately, you can specify
three-dimensional coordinates for each of the parts that will make up
the final object. The latter approach is used by video games and in
the fancy special effects used in movies. A video game may store a
3D object as a series of 3D coordinates, and then use such
coordinates to construct the object virtually.
A different approach
for telling how to make a three-dimensional object is what we may
call the recipe approach or the algorithm approach. When this
approach is used, you merely specify a list of ingredients or parts
and a list of steps or operations that will be taken using such
ingredients or parts. For example, you might specify steps for
making a house without using any blueprint for the house. You could
specify a list of building materials and a list of exact operations
to be performed on those building materials – a set of
instructions. If the set of instructions was sufficiently detailed,
they might be sufficient to produce some exact type of house.
But the “language”
used by DNA is a minimal type of language that lacks any capability
for using either of these approaches. Instead of being a rich
language capable of great expression, the language used by DNA is
pretty much the poorest, most “bare bones” type of language you
can imagine. It's a language unsuitable for purposes other than
stating lists of chemicals.
Let's look at
exactly how the “language” of DNA works (and I used the word
“language” in quotation marks because the expression capability
is so limited that it may be an exaggeration to even say that it uses a
language). DNA is a molecule containing many nucleotide base pairs,
as shown in the diagram below. The base pairs can be either adenine,
guanine, cytosine, thymine, or uracil.
Combination of these “letters” of the DNA alphabet are used to represent
particular amino acids, which are the building blocks of proteins.
You have to look at a diagram of the genetic code to understand how
particular combinations of these base pairs stand for particular
Now this “language”
is incredibly constrained. Basically the only thing that you can
specify with it are lists of amino acids. To get an idea of how
limited this is, imagine if you never learned more than 20 words from
your parents or teachers, each the name of some food. Your powers of
expression would then be incredibly limited. You might be able to
describe some kind of sandwich you wanted by saying something like
But you absolutely
could not specify something like a plan for making a building, a
complex machine, or a complex 3D object consisting of many parts
existing in different coordinates in three dimensional space.
And so it is for
DNA. The “language” used by DNA is effectively 24 words or
fewer. Twenty of those words are nouns, each an amino acid. The only
verbs are something like the words “start” and “stop,” and
possibly also “use” and “ignore.” I include those two words
because scientists say that particular genes can be turned on or off.
table below gives a schematic view of the DNA language. Strictly
speaking the only verbs supported are “start” and “stop,” but
I have also added “use” and “ignore” to cover the idea of
genes that are switched on or switched off.
You can practice at
talking in the DNA language. Here is the algorithm:
State any one of
the twenty amino acids in the list above.
Repeat step (1) any
number of times.
When you're done,
Get the picture?
Below are some examples of “talking in the DNA language.”
When you try this a
few times, you may realize the very small powers of expression of
this tiny little DNA mini-language.
“blueprint” approach of specifying a three dimensional object. A
piece of DNA cannot specify that some particular body part should
exist at some position in 3D space, because the DNA has absolutely no
way of expressing positional coordinates. There is no way to say
“behind,” “below,” “above,” or “in front of” using
DNA, nor is there any way of specifying how much farther something
might be behind, below or above something else. Not only is DNA
language incapable of expressing where a nose should be located, the
language also cannot even express the idea of a nose. All that DNA
can do is to specify some proteins that might be used by the nose.
Even that specification is incomplete, because DNA only tells which
amino acids are used by a particular protein – it does not specify
the shape of a protein (proteins typically have extremely complicated
3D shapes involving lots of folding and twisting).
But what about the
“recipe” way of specifying something – can DNA do that by
expressing a complex algorithm or list of steps such as we would need
to have a program for making the human body? No, it cannot.
Expressing an algorithm like that requires a language capability
that DNA doesn't have. Consider types of instructions contained in
recipes or algorithms:
this step 13 times
doing this step until condition X is met
doing this step but stop when condition Y is met
visible part X so that it is connected to visible part Y
Such ideas cannot be
expressed by the “bare bones” language of DNA, which can only
express lists of amino acids used to make proteins or nucleic acids.
It seems clear,
then, that the language limitations of DNA mean that it cannot be
something that expresses a blueprint for a human being or a recipe
for making a human being. DNA is not a program for making a human.
#2: Even if the “language” used by DNA had the capability of
expressing a blueprint or recipe or program for making a human, there
would be nothing that we know of capable of interpreting such
important fact to consider is that a list of instructions is not
sufficient by itself to cause something to get done. You always need
some sophisticated agent smart enough to interpret the instructions
and execute them. We know this is true for something like a food
recipe. Obviously an apple pie won't get cooked just because you have
an apple pie recipe on your table – you need a human smart enough
to read those instructions and execute them. But what people
sometimes forget is that something similar holds true even for
computer code. If I write a computer program in some new language
called Lingua, just putting that source code on my computer will
never cause the program to run. I would also need to have on my
machine a highly sophisticated piece of software called an
interpreter, something that is reading each of those instructions,
and causing some corresponding action to be taken.
What is the
relevance of this to DNA? The relevance is that not only do we know
of no capability that DNA's “language” has for specifying
anything like a three-dimensional blueprint or an algorithm for
making a visible three-dimensional object, but we also know of no
capability in the body for interpreting such instructions if they
existed. So in order for DNA to work as a program for generating the
human body, we would need two things: (1) some capability by which
DNA could express complex instructions for making visible
three-dimensional objects (which are apparently completely beyond the
limitations of DNA's feature-poor, minimalist language); (2) some
other capability by some other unknown agent capable of acting as a
highly sophisticated interpreter of these complex instructions.
Neither of these things is known to exist.
It would seem,
therefore, that the idea that DNA acts as a program or algorithm for
generating the human body is not just impossible, but doubly
#3: Despite cataloging the entire human genome, and exhaustively
analyzing it, scientists have not discovered any part of DNA where a
blueprint of the human body or a recipe for making humans is stored.
The Human Genome
Project was a federally funded project that completed in April, 2003,
after cataloging the entire human genome (all parts of DNA). It was
followed up a federally funded ENCODE project designed to further
analyze DNA. The results were gradually released over the next
decade. Now with all this exhaustive study and analysis, we would
expect that if there existed such a thing as a blueprint for the
human body in DNA or a recipe for making the human body in DNA, that
it would have been discovered. But no such thing has been discovered.
We have discovered in DNA mainly just a list of chemicals used in
constructing proteins, not anything like a specification specifying
the body plan of humans or how to construct the intricate machinery
of the human body.
we look at the genes that are most commonly cited as something that
may constitute something like body plan information, we find meager
evidence indeed: the murky case of what are called hox genes. It has
been claimed that hox genes “control the body plan of an embryo
along the cradial-caudal (head-tail) axis” by means of a tiny area
called the homebox. But the evidence for this claim is very weak.
Geneticist Jerry Coyne says this about hox genes: “Their
overall function in development - let alone in evolution - remains
I may note
that the “homeobox” supposedly having some relevance to the human
body plan is only 180 nucleotides long (the equivalent of about 60
words in the DNA language). This is millions of times too small to
store anything like a plan for the human body.
unwarranted claims about Hox genes are summarized by Joseph
Hannon Bozorgmehr at the Laboratory of Systems Biology and
Bioinformatics at the University of Manchester (author of this scientific paper).
Bozorgmehr writes the following :
code for proteins and RNAs. They don't code for brains, limbs or body
plans. Yet many scientists insist that Hox genes, and other
transcription factors, are responsible for "laying out the floor
plan" of the organism when all they are observed to do is
activate genes in already established segments of the developing
embryo. We have known this for 20 years. So why are the 39 Hox genes
still portrayed as determining the geometry of anatomy when all they
do is bind to DNA and RNA polymerase to affect gene expression in
The meager and murky
evidence regarding hox genes notwithstanding, our scientists have not
found any clear evidence that DNA stores a blueprint for the human
body, a recipe for the human body, or any type of program or
algorithm like a body plan. If DNA stored such a thing, there would
be abundant evidence of it.
the short video below, Jonathan Wells (a PhD in molecular
and cell biology from the University of California at Berkeley)
states very clearly that DNA does not map out a body plan. He states
“the body plan, as far as we know, is not in the DNA” (0:33),
and states that DNA is “not a blueprint, it's more like a parts
#4: If DNA stored a human blueprint or human recipe or body plan,
humans would have a much larger DNA than simpler organisms; instead,
the opposite is often true.
body plans are stored in DNA, we should expect that the size of an
organism's DNA should be proportional to the size and complexity of
an organism. For the same reasons that the blueprints of a skyscraper
use much more paper than the blueprints for a house,under a “DNA has
the body plan” assumption we should think that the human DNA is
much bigger than the size of, say, any flowering plant. But astonishingly, the
opposite is true. The charthere shows the relative size of the DNA
in different organisms. We see that the size of the DNA (in base pairs) in mammals is
much smaller than the size of the DNA of many amphibians and flowering
plants. We see on this logarithmic chart that the DNA of some
amphibians and flowerings plants holds ten times more information
than the DNA of humans.
A related comparison
is the number of genes in the DNA. According to this link, rice has
between 32,000 and 50,000 genes, while humans have only 20,251 genes.
That's the opposite of what we would expect if DNA stored body plans.
#5: The DNA size of humans is insufficient to be a blueprint or
recipe for the human body with all its complexities.
biologists have sometimes assumed that DNA is a complete
specification for constructing a human body, but I have never once
read a biologist consider whether the information size of DNA is
sufficient for such a task. The idea that DNA can store a complete
specification for a human being will obviously make no sense if our
DNA molecules are not big enough to store such a specification, just
as it will make no sense to assume that a postcard can store the
names of all members of a club if the club has many thousands of
It has been
estimated that a DNA molecule has an information size of about 700
megabytes. This is not big enough to store a complete blueprint,
algorithm, or program for creating a human being. If you use the
uncompressed RAW files used in cameras, it will take about 8 megabytes to store a high resolution photo. This means human DNA has
an information size needed to store about 100 high-resolution photos
uncompressed. This is not big enough to store a complete
specification for making the human body. A recently introduced CT
scanner requires 320 scans to map a human body, each scan equivalent
to such an 8 megabyte photo. But consider also all the microscopic
functionality that would need to be specified, and all of the
microscopic details. It would seem that it would require many
gigabytes to store a complete plan for building a human, not just 700
#6: If DNA stored a recipe or blueprint for making humans, we would
probably sometimes see extremely jumbled bodies resulting from
mutations, but we don't see such “scrambled humans.”
This is the weakest
of my six reasons, so I'll discuss it only briefly. All parts of DNA
are subject to mutations in which random changes occur because of
things such as copying errors and cosmic rays hitting part of DNA.
If DNA stored the human body plan, it seems that we should expect to
see weird examples of “scrambled humans,” such as people born
with eyes on their cheeks, people with noses on their chins, people
born with ears on their foreheads, and so forth. But we don't see
such abnormalities. Genetic mutations can produce serious
abnormalities, but the human body seems to be implemented with
astonishingly fidelity, more so than we would expect if the body plan
for humans was stored in DNA subject to mutations.
Gigantic Missing Link of Life
discussed above strongly argue that DNA is not a blueprint, recipe or
specification for making a human being. Does this mean that there is
nothing like a body plan for making a human? Not at all. Such a plan
must exist somewhere. But we don't know where it is located. It does
not exist in DNA. Widely described as “the secret of life,” DNA
must instead be only one secret of life. There must be some other
equally great secret that we have not discovered.
secret – the unknown location of the specification for making a
human being – is the gigantic missing link of biological life that
we have not discovered.
Where might such
information be stored? It might possibly be stored somewhere else in
the body, or it might be stored outside of the body. It may well be
that the answer lies in some field or force or influence or
information system entirely unknown to us.
missing link of life can most mysteriously be seen at the moment of
life's conception. Once a tiny female ovum has been fertilized by a sperm,
how does the fertilized ovum know how to turn into a human baby,
rather than a million other possible forms? There is absolutely not
in DNA any mechanism by which an ovum or an embryo can look up a list
of instructions to follow based on its age. An ovum or an embryo
doesn't know how old it is, and doesn't know where to look in DNA to
look up appropriate instructions; and DNA does not have instructions
organized by biological age, which might be looked up by some ovum or
embryo that knew its age. DNA has everything written in a language of
about 22 words in which 20 of those words are amino acids – not
something remotely suitable for stating any instructions other than
protein or RNA assembly instructions.
As Jonathan Wells
(a PhD in molecular and cell biology) states near the end of this lengthy scientific
idea that embryo development is controlled by a genetic
program is inconsistent with thebiological
evidence. Embryo development requires far more ontogenetic
information than is carried by DNA sequences.
The problem of how a
fertilized ovum can progress to a baby is called the problem of
morphogenesis. It is an unsolved mystery that modern biology has not
given enough attention. The complete answer must involve much more than just DNA,
and we have every reason to suspect that it involves something
utterly mysterious that we know little or nothing about. Until this
mystery is solved, we cannot plausibly claim that we understand
either life or evolution.
Postscript: My point about morphogenesis and evolution is pretty much reiterated in this book "Morphogenesis and Evolution," where Keith Stewart Thomson (president of the Academy of Natural Sciences in Philadelphia) stated the following (at the beginning of Chapter 7):
J. Maynard Smith (1983) has written that "althoughwe have a clear and highly articulated theory of evolution, we have no comparable theory of development."I would turn this statement around somewhat and say that until we have a general theory of developmentwe are unlikely to be able to derive a complete theory of evolution.
Correct, and you could just as easily change that phrase "complete theory of evolution" to "plausible theory of what drives evolution."
In this .pdf file, a professor of Mathematical Biology makes this statement:
genes obviously play a role in development,
knowing the genetic make-up of an organism
does not allow us to understand the mechanisms
of development—we may know that
certain genes impart particular properties to certain
cells, but how this then leads to tissue-level
behaviour cannot be addressed by genetics.
That is basically a fancy way of saying that a fertilized ovum does not become a baby by following a body plan stored in DNA.
On page 26 of the recent book The Developing Genome, Professor David S. Moore states, "The common belief that there are things inside of us that constitute a set of instructions for building bodies and minds -- things that are analogous to "blueprints" or "recipes" -- is undoubtedly false."
Biologist Rupert Sheldrake says this about this issue:
DNA only codes for
the materials from which the body is constructed: the enzymes, the
structural proteins, and so forth. There is no evidence that it also
codes for the plan, the form, the morphology of the body. To see this
more clearly, think of your arms and legs. The form of the arms and
legs is different; it's obvious that they have a different shape from
each other. Yet the chemicals in the arms and legs are identical. The
muscles are the same, the nerve cells are the same, the skin cells
are the same, and the DNA is the same in all the cells of the arms
and legs. In fact, the DNA is the same in all the cells of the body.
DNA alone cannot explain the difference in form; something else is
necessary to explain form.
An evolutionary biologist notes that "the long-held belief that genes are the unique determinants of biological form in development and evolution has been challenged by an extensive number of commentators." Among these "extensive number of commentators" are the people mentioned above and the authors of this scientific paper, who note that "gene expression patterns cannot explain the development of the precise geometry of an organism and its parts in space."
Describing conclusions of biologist Brian Goodwin, the New York Times says, "While genes may help produce the proteins that make the skeleton or the glue, they do not determine the shape and form of an embryo or an organism." Massimo Pigliucci (mainstream author of numerous scientific papers on evolution) has stated that "old-fashioned metaphors like genetic blueprint and genetic programme are not only woefully inadequate but positively misleading." Neuroscientist Romain Brette states, "The genome does not encode much except for amino acids."
In a 2016 scientific paper, three scientists state the following:
is now clear that the genome does not directly program the organism;
the computer program metaphor has misled us...The genome does
not function as a master plan or computer program for controlling the
organism; the genome is the organism's servant, not its
master....Metaphorically, we can think of the genome as akin to a
list of words, a vocabulary, which can be used to build and express a
meaningful language; like a vocabulary, a genome by itself has no
functional meaning. The genome is thus akin to a toolbox of DNA
sequences that provide molecular tools as requested by the internal
state of the organism and the state of the environment. One's genes
cannot explain one's being: an organism is the expression of a
dynamic and ongoing interaction between the state of its environment
and its internal state, which includes its past history and its
toolbox of DNA sequences.
In the book Mind in Life by Evan Thompson (published by the Belknap Press of Harvard University Press) we read the following on page 180: "The plain truth is that DNA is not a program for building organisms, as several authors have shown in detail (Keller 2000, Lewontin 1993, Moss 2003)."