The
Cat and the Hat
And the Evolution of Code
Sean Pitman M.D.
© July 2003
A
man walks into a store and tells the clerk, "I'm looking to buy a hat."
The clerk says, "We are all out of hats, but I do have a cat
that I
will sell to you at a good price." The
man tells the clerk, "Close enough. I'll
take it."
This
is just silly - right? A cat is
nothing like a hat despite the fact that the words look and sound
similar.
The point is, words are just arbitrary symbolic representations
of ideas.
The letters or symbols in a word mean nothing unless they are
assigned a
meaning by an outside source (like a dictionary or a codebook).
Because of the arbitrary nature of language any symbol or group
of
symbols can be assigned any definition, as long as it is agreed upon or
understood by those who wish to use symbols to communicate ideas.
In this way, some very similar ideas can be represented by very
different
looking words or some very different ideas can be represented by some
very
similar looking and sounding words. For
example, the words "Admire" and "Esteem" have very similar meanings,
but
look nothing like each other. The
words "Vacation" and "Vocation" look and sound very similar, but have
very different meanings. Why?
Because of the arbitrary nature of language.
All languages are arbitrary in that written or spoken symbols
(or other
symbols such as are used in sign language) are given their meaning and
this
meaning is independent of and greater than the symbols themselves.
Symbolic
languages are not just limited to human communication.
Every living thing uses symbolic language to communicate
information.
How? In the form of genetic
words written in the languages of DNA and protein.
If you are interested in the details, just look in any basic
biology
textbook, and you will find that the language of DNA is made up of
words.
Each of these words is given an arbitrary meaning by a codebook
called
the "Genetic Code." Proteins
are also "written" using letters in a chemical alphabet called amino
acids.
There are 20 different amino acids just as there are 26
different letters
in the English alphabet. Different
arrangements of these letters in proteins spell out protein words,
which are
given an arbitrary meaning or function by the cell that makes them.
Just as in any other symbolic language, there is no inherent
meaning for
a given protein outside of the how the cell defines it.
For example, the protein called "insulin" is a signal to some
cells
in the human body to uptake sugar (glucose) from the blood stream.
The insulin protein (Bovine Insulin) is made up of two protein
words that
are linked together. One of these
words is 21 letters (amino acids) in length.
The other word is 30 letters in length.1
There is nothing special about these words in and of themselves
that
tells a cell that it needs to uptake sugar.
So, how does the cell “know” what to do when it comes in contact
with
insulin? The cell recognizes
insulin. But how does the cell
recognize insulin? The cell has a
specific receptor protein that senses insulin like a lock recognizes a
key.
Then, just like when a key turns a lock, this insulin receptor
sends a
signal to the cell that tells it to uptake sugar.
In other words, this lock is linked to an underlying system of
function.
The key that it recognizes is the insulin key, but this
recognition is
arbitrary. The same function could
in fact be set up to recognize any other protein "word" or "words."
The fact that it recognizes insulin is strictly arbitrary, just
as in any
other symbolic language. The
insulin molecule is simply a symbolic representation of an idea or a
function
that the cell recognizes. The cell
recognizes insulin because it is programmed to recognize the language
of the
body or "system" that it is a part of.
Specialized cells make the insulin protein as a symbolic message
to other
cells in the body that tell them when and how they need to use the
blood sugar
that is available to the body. They
could just as easily have been programmed to use some other protein
molecule or "word" for the same purpose. The
fact that living creatures use symbols to send messages and to perform
functions
is undeniable. The fact that these
messages are arbitrary and dependent upon a pre-established code of
definition
also seems intuitive.
The
question now is, how did these arbitrary languages and words of living
things
come about? For the English
language, and all other known languages, the ideas come first, and then
the
symbolic expressions of the ideas (since the symbols themselves have no
inherent
meaning). The letters, "cat"
mean nothing aside from the attached idea that is arbitrarily given
them by the
English dictionary (or the English speaking "environment").
Likewise, the letters in the insulin molecule mean nothing
outside of the
attached meaning given to them by a living cell or system in a
particular
environment. Do words change their
meaning through an evolution of random letter changes, or through an
evolution
of ideas, which then seeks out some symbolic representation?
If I change the letters "cat" to read "hat", does this change
necessitate an evolution of recognition or function in and of itself?
Obviously not because if the change read “cct” this change would
have
no meaning. Why?
Because “cct” is not defined in the English
dictionary/environment as
being meaningful much less beneficial in a given situation.
Remember, the symbols or letters themselves have no inherent
meaning
whatsoever. Definition and
recognition must always come before a symbolic representation.
So, if I change the letters in the insulin words around, would
these
changes necessitate a change in cell recognition and function?
No, of course not. In fact,
if the letters in the insulin words change too much, the cell would not
recognize the new molecule at all. Why?
Because this new protein may not be defined in the cell’s
dictionary of
protein words.
However,
is it possible to change a letter of a word randomly and have it mean
something
in the English dictionary? Of
course it is, but this change would need to have had a pre-existent
definition
waiting for it in the dictionary. Changing
the "c" in the word "cat" to an "h" in the word
"hat" does in
fact change the understood definition at the same time - but why?
Because, both of the words, "cat" and "hat" were pre-defined by
the English dictionary/environment. Similarly,
it would be possible to change insulin into another protein that did in
fact
have function - if the cell or organism had a pre-established system
that
recognized this "new" protein.
Now, let me pose a scenario. Regis Philbin is the host of a game show called "Millionaire or Not" and you are the next contestant. In front of you is a safety deposit box with a million dollars in it. On the front of the box is an apparatus that looks like a slot machine. It has 15 rotating wheels, each with the 26 letters of the alphabet on it. Regis tells you that there are one million different winning combinations of fifteen letters that will open the safety deposit box. You can rotate each wheel at will and then press a button to see if the combination that you chose is one of the one million winning combinations. You can keep doing this until you give up. You think that this game is a synch. With one million winning combinations possible, you are practically guaranteed to win. However, if you never choose the same combination twice and if you test a new combination every second, how long will it take you on average to find any one of the one million correct combinations? It would take you a bit over 53 million years on average. It is definitely not as easy as it looks anymore is it? It sure would help if you could figure out which combination that you chose was “closer” to any of the winning combinations now wouldn’t it? However, there is no function except the winning “function” to any combination that you try. There is no "close" function. No lights go off when you are getting "warmer" or "colder." You see, without some indication, without some intelligible function or signal attached to the losing combinations, you are completely in the dark as far as your ability to know if you are even getting close to a winning combination.
Likewise, in living cells, there are far less usable or recognized proteins than there are possible proteins as one moves up the ladder of functional complexity. Obviously, like simple words with simple functions, there are also simple proteins with simple or very general functional capabilities. All real-time examples of evolution in action point to functional changes in proteins that are very simple in functional complexity (such as examples of antibiotic resistance and other types of drug resistance). However, as with the English language, there are levels of functional complexity when it comes to cellular functions.
Getting from one "beneficial" protein to another "beneficial" protein by random mutation is next to impossible above a certain level of specified complexity (which is determined by both the cellular makeup as well as the environment). There is a gulf of neutral or even detrimental protein sequences between potentially beneficial proteins that expands exponentially with increasing levels of functional complexity. During the crossing of such neutral oceans of function, there is no way for nature to detect when a neutral protein is getting closer to a beneficial sequence. The reason for this is because nature is blind without an ability to detect a change in function with a neutral change in symbolic sequence just as a player of "Millionaire or Not" would be blind without an ability to detect any change in function between each new non-winning change in the 15-letter sequence.
Certain functions, like antibiotic resistance functions, are extremely simple to evolve because they are based on changes that interfere with or destroy other pre-established functions or interactions. An antibiotic's interaction with it's target is very specific. Often, very slight changes or mutations are all that are needed to interfere with this interaction. Obviously, the ratio of interfering proteins as compared to the total number of potential protein sequences (the total number of possible protein words) is very high. In other words, there exist in the potential pile of protein words a very large number of proteins that would not react very well with the antibiotic. Because of this high ratio of interfering proteins, the odds that a change in the original protein would end up on an interfering protein are very high. Thus, the evolution of resistance to this antibiotic is very likely. This phenomenon is clearly supported by the real life ability of bacteria to overcome just about any antibiotic that comes their way in very short order. Clearly, this is a real time example of evolution in action, but the new function that was evolved here was obviously of the lowest level of functional complexity. Consider that it was much easier to break Humpty Dumpty than it was to put him back together again. Every child knows this law of nature. It is far easier to destroy than it is to create.
Why is this? Why is it easier to destroy than it is to create from scratch? The reason is that there are a lot more ways to destroy than there are to create. There are a zillion more ways to break a glass vase than there are to fix or create that glass vase to begin with. The same thing holds true for the various functions in living things. They are like glass vases.
The evolution of antibiotic resistance via changes to a target sequence was easy because it involved the breaking of an established function/interaction. However, many more functions exist in living things that cannot be created by breaking some pre-established function. The relatively simple function of single protein enzymes is a good example of this. There is certainly no way to get the penicillinase enzyme (another method of antibiotic resistance - but the penicillinase enzyme does not evolve in real time) to evolve by disrupting some other interaction. The same is true for the lactase and nylonase enzymes. The functions of these enzymes cannot be realized by interfering with other pre-established functions. Experiments which include the evolution of the lactase enzyme in E. coli (a study done by Professor Barry Hall), and the evolution of the nylonase enzyme (from a paper by Kinoshita, et. al.), to name just two of many such examples, demonstrate this phenomenon nicely.10,11,12 What Hall showed is that if some genes are deleted in living cells like E. coli, they are simply incapable of evolving certain specified functions, such as the lactase ability, despite strong selection pressures and thousands upon thousands of generations of time. Professor Hall himself described such colonies of bacteria as having, "limited evolutionary potential." What is especially interesting about such experiments is that these same colonies of bacteria would be able to evolve antibiotic resistance to just about any antibiotic presented to them in short order. And yet, they simply could not evolve the relatively simple lactase function over the course of tens of thousands of generations?
So it is clear that although single protein enzymes might be fairly simple when compared to other cellular functions, they are still fairly complex in that the ratio of sequences with a particular or specified type of enzymatic function is fairly low when compared to the total number of potential protein sequences or "words". Even so, the ratio is often high enough so that on relatively rare occasions, large populations of bacteria can and have been shown to evolve unique beneficial functions that are based on the potential of single protein enzymes (i.e., the lactase and nylonase functions - as well as many other such examples are clearly examples of the de novo evolution of brand new functions that are not dependent upon the loss of any other known cellular function). Despite their demonstrated evolution, this evolution is obviously much more difficult to come by than examples of the evolution of functions of lower levels of specified complexity (such as the de novo evolution of antibiotic resistance).
The
problem for the theory of evolution is found in the fact that the
ladder of
function complexity keeps going up. The next rung up this ladder
of
functional complexity includes those functions that require multiple
proteins
all working together at the same time in a specified arrangement with
each
other. Examples of this level of cellular function include
functions like
bacterial motility systems (like the flagellar apparatus which requires
around
50 or 60 parts all working together at the same time in a specified
arrangement
or order). Interestingly enough, when it comes to this
level of
specified functional complexity there simply are no examples of
evolution in
action - period. No one has ever demonstrated the evolution of a
multi-protein system of function (of even a few proteins) where all of
the
protein parts are working together at the same time in a specified
arrangement.
I propose that the reason for this is that ratio of protein sequences
that could
give rise to such a specified function at this level of functional
complexity is
truly miniscule when compared to the total number of proteins in the
vast ocean
of potential protein "sentences/paragraphs". This tiny ratio of
what will work as compared to what won't work creates a neutral gap
between
various potentially beneficial functions at this level of complexity
that is
simply too wide for the random walk of random mutations to overcome -
even in
trillions upon trillions of years.
The
Theory of Evolution is in serious crisis because of this very problem
although
many have tried to explain away this problem.
One valiant attempt was made by the famous British evolutionary
biologist
Richard Dawkins. In his 1986 book
called “The Blind Watchmaker” Dawkins described an experiment of his
that
showed how evolution is supposed to work. He
programmed a computer to generate random sequences of letters to see if
the
computer would, over time, generate the line from Hamlet, "METHINKS IT
IS LIKE
A WEASEL." This line has 28
characters (including spaces), so the computer was programmed to make
28
selections using the 26 letters of the alphabet plus a space to make 27
possible
characters to pick from. A typical
output was "MWR SWTNUZMLDCLEUBXTQHNZVJQF." With this information, a calculation of the probability of
picking the "correct" sequence can be made, as well as how long it would take, on
average, to find this correct sequence. Dawkins
figured that it would take his computer a million million million
million
million million years (or a trillion trillion trillion years… 1 x 1036
years), on average. Well, this is
clearly way too long for the current theory.
So, how could evolution possibly take place?
Dawkins now put some “natural selection” into the computer
program to
simulate "real life" more closely. The
computer made multiple copies of "MWR SWTNUZMLDCLEUBXTQHNZVJQF"
(Offspring)
while introducing random "errors" (mutations) into the copies.
The computer then examined all the mutated "offspring" and
selected
the one that had the closest match to, "METHINKS IT IS LIKE A WEASEL."
This selection by the computer (nature) was now used to make new
copies
and random mutations (in a "new generation"), from which the best copy
was
selected again… and so on. By ten "generations" the sequence had
"evolved" to read, "MDLDMNLS
ITJISWHRQEZ MECS P." By the
thirtieth generation it read, "METHINGS IT ISWLIKE B WECSEL." Instead of taking many trillions and zillions of years this
time, the
computer came up with the "fittest" phrase in only forty-three
generations.2
Yes,
Dawkins does make a disclaimer about this experiment saying that it is
not
intended as a demonstration how real evolution works. He says
that it is
only an example to show how a selection mechanism gives an advantage
over time.
Even so, I still fail to see the relevance to the theory of evolution.
The most obvious problem is that the computer already had the "correct" phrase programmed into it ahead of time, which it could use
to
compare any future phrases to see if they were getting closer.
Evolving something that is already there is not the evolution of
anything
new at all. If nature already has
what it wants or needs, then it does not need to "evolve" it.
I mean really, if computers could be so easily creative in the
way
Dawkins describes, then we would not need Shakespeare now would we?
Another
problem with Dawkins’s illustration is that nature cannot select for
what is
not functioning. Nature does not "see" the actual letters of words (in DNA or Protein).
All that nature can see is what function results.
Since function is arbitrarily attached to words by an outside
source of
information as previously described, a gradual change in the letters of
the
words themselves is not going to result in a gradual evolution of their
meaning
or function beyond the lowest levels of functional complexity.
A gradual letter by letter change in a beneficial collection of
words/sentences will most likely destroy their original collective
meaning well
before any new beneficial function of the same level of complexity is
realized.
The reason for this limitation can be found in the neutral gap problem
that is
created by the exponential expansion of the pile of "junk proteins" as
the level of complexity increases. This neutral gaps blinds the
abilities
of natural selection to guide evolution to new functions of increasing
complexity. Neutral changes do not result in functional
changes. Without
functional changes along the entire path toward a new function, natural
selection is blind. Without natural selection as a driving force,
even
Dawkins will admit that evolution is statistically impossible.
Michael
Behe, a professor of biochemistry at Lehigh University, says that,
"Molecular evolution is not based on scientific authority.
There is no publication in the scientific literature in
prestigious
journals, specialty journals, or books that describe how molecular
evolution of
any real, complex, biochemical system either did occur or even might
have
occurred. There are assertions that
such evolution occurred, but absolutely none are supported by pertinent
experiments or calculations."3
Should these facts be pasted by unacknowledged by the scientific mind? It seems like evolutionary theories have had ample time to prove themselves. "It is good to keep in mind ... that nobody has ever succeeded in producing even one new species by the accumulation of micromutations. Darwin's theory of natural selection [as a creative force beyond the lowest levels of functional complexity] has never had any proof, yet it has been universally accepted."4
If
significant evolution could happen in just a few generations as Dawkins
indicates, then why is it not being observed in cells like bacteria
that have
very short generation times? Over
the past 50+ years, greater than one million generations of E.
coli have been observed, radiated, drugged, burned, frozen,
dissected,
mutated, selected and manipulated in every conceivable manner (talk
about
selection pressure), and yet E. coli is still E. coli.?
This seems especially strange when one considers that humans
supposedly
evolved from apes in less than 200,000 generations using a much lower
mutation
rate (on the order of one mutation per gene per 100,000 generations).8,9
Dr. Robert Macnab seems to be asking the same question when he
comments
that "…one can only marvel at the intricacy in a simple bacterium, of
the
total motor and sensory system which has been the subject of this
review and
remark that our concept of evolution by selective advantage must surely
be an
oversimplification."5 Gordon
Taylor also observes, "In all the thousands of fly-breeding experiments
carried out all over the world for more than fifty years, a distinct
new species
has never been seen to emerge."6
"...An
intelligible communication via radio signal from some distant galaxy
would be
widely hailed as evidence of an intelligent source. Why then doesn't
the message
sequence on the DNA molecule also constitute prima facie evidence for
an
intelligent source? After all, DNA information is not just analogous to
a
message sequence such as Morse code, it is such a message sequence."7
Has
Design Theory come full circle? Many,
even among the most respected of scientific minds, seem to be giving it
more
than another look.
1.
Stryer, Lubert. Biochemistry,
3rd ed., 1988, pp. 153, 744.
2.
Dawkins, Richard. The Blind
Watchmaker, 1987.
3.
Behe, Michael J. Darwin’s Black
Box, The Free Press, 1996.
4.
Goldschmidt, R. PhD, DSc Prof. Zoology, University of Calif. in Material
Basis of Evolution, Yale Univ. Press.
5.
Macnab, Robert. Yale University, Bacterial
Mobility and Chemotaxis: The Molecular Biology of a Behavioral
System, CRC
Critical Reviews in Biochemistry, vol. 5, issue 4, Dec., 1978, pp.
291-341
6.
Taylor, Gordon. The Great
Evolution Mystery, New York: Harper and Row, 1983, pp 34, 38
7.
Thaxton, Charles B. Walter L Bradley and Robert L Olsen:
The Mystery of Life's Origin, Reassessing Current Theories, New
York
Philosophical Library 1984, pp 211-212.
8.
Dugaiczyk, Achilles. Lecture
Notes, Biochemistry 110-A, University California Riverside, Fall
1999.
9.
Ayala,
Francisco J. Teleological Explanations in
Evolutionary Biology, Philosophy of Science, March, 1970, p. 3.
10. B.G. Hall, Evolution on a Petri Dish. The Evolved B-Galactosidase System as a Model for Studying Acquisitive Evolution in the Laboratory, Evolutionary Biology, 15(1982): 85-150.
11. Kinoshita, et. al.,"Purification and Characterization of 6-Aminohexanoic-Acid-Oligomer Hydrolase of Flavobacterium sp. K172," Eur. J. Biochem. 116, 547-551 (1981), FEBS 1981.
12. Susumu Ohno, "Birth of a unique enzyme from an alternative reading frame of the pre-existed, internally repetitious coding sequence", Proc. Natl. Acad. Sci. USA, Vol. 81, pp. 2421-2425, April 1984.
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