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SanGene 09-01-006 |
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Genetic Entropy & The
Mystery of the Genome Dr. J. C.
Sanford Elim
Publishing, 2005, 208 pp., ISBN 1-59919-002-8 |
Dr. John
Sanford is a semi-retired researcher and plant geneticist from Cornell
University. The complexity
of a bacterium, the simplest form of life, is as great as that of the space
shuttle. And the jump in complexity
from a bacterium to a human is as great as from a little red wagon to the
space shuttle. So far we
have discovered only the first dimension of this "book of life," a
linear sequence of 4 types of nucleotides.
Small clusters, or motifs, of these four molecular letters make up the words which combine to form genes,
the chapters, which combine to form
chromosomes, the volumes,
which combine to form the whole genome, the entire library of instructions for life. "The
genome is the instruction manual which specifies life." "An organism's genome is the sum total
of all its genetic parts, including all its chromosomes, genes, and
nucleotides." (1) A complete
human genome consists of two sets of 3 billion individual 'letters' each. A
fraction of this library encodes 100,000 human proteins. (2) "Each
of these protein and RNA molecules are essentially miniature machines, each
with hundreds of component parts, each with its own exquisite complexity,
design and function." (3) "The
genome's set of instructions is not a simple, static, linear array of
letters; but is dynamic, self-regulating, and multi-dimensional. There is no human information system that
can even begin to compare to it." (4)
"Each human body contains a 'galaxy' of cells (more than 100
trillion), and every one of these cells has a complete set of instructions
and its own highly prescribed duties."
Carl Sagan said each cell contains more information than the Library
of Congress. (4) "The
standard answer to the origin of biological information is that mutation combined with selection have created all biological
information." This the Primary
Axiom of biological evolution. (5)
"No intelligence is involved in this scenario." Natural selection is a term for a blind and
purposeless process whereby some things reproduce more than others. (8-9) "An
Axiom is an untestable concept, which is accepted by faith because it seems
so obviously true to all reasonable parties.
On this basis, it is accepted as an Absolute Truth." (5) This book questions whether we should
accept today's Primary Axiom. (5) "Mutations
are complex and happen at the molecular level, but selection can only be
carried out on the level of the whole organism." (6) "Random
mutations consistently destroy information." (15) Random variation is like what happens to
your car over time: dings, rust and breakage.
Typographical errors do not improve a student's paper and throwing rocks
does not improve glass houses.
Alternative, designed variations may improve your car, your paper, or
your house. "Part of the Primary
Axiom is that all genetic variation must come from random mutations, since no
genetic variation by design is allowed."
However, it can reasonably be argued that random mutations never
improve quality. (16) "I am still not convinced there is a
single, crystal-clear example of a known mutation which unambiguously created information. Some random changes may be beneficial (like
a broken car alarm to a thief), and some plants may be more useful or pretty
because of a loss of a cell function, for example. But no new information is created. (17) "I
have seen estimates of the ratio of deleterious-to-beneficial mutations which
range from one thousand to one, up to one million to one." The actual rate is so low as to thwart any
real measurement. (24) Even when a
mutation is beneficial, it usually represents part of an over-all erosion of
information. (27) Human
mutation rates are much too high. (33)
It is at least 100 nucleotide substitutions (misspellings) per person
per generation. (34) "It is
becoming increasingly clear that most, or all, of the genome is
functional. Therefore, most, or all,
mutations in the genome must be deleterious." (39) With 6 billion people adding 100 new
mutations each, our generation alone has added roughly 600 billion new
mutations to the human race. This degenerative
process will continue. We are on a
downward slide. (40) "Mutational
meltdown is recognized as an immediate threat to all of today's endangered
species. The same process appears to
potentially be a theoretical threat for mankind. What can stop this process?" (41) The
decline in our species fitness is estimated at 1-2% per generation. (45) Natural
selection is a very real phenomenon and it has very real capabilities and
very real limitations. (46)
"Selection acts on the level of the organism, not on the level of
the nucleotide." (54) "There
must be a vanishingly small
correlation between any given nucleotide (a single molecule), and a whole
organism's probability of reproductive success!" "It is a little like trying to select
for a specific soldier, based upon the performance of his army." (49)
For analogy, suppose each student is given a biochemistry text with
random misspellings, duplications, and deletions. At the end of the course, you save the
textbooks of those students who got the best grades. The noise
(other factors) will easily override the effect of the textbook errors.
(50) The textbooks will obviously
degrade over time and average student scores will eventually go down. While such a blind process will never
improve textbooks, the Primary Axiom
claims that this mutation/selection process wrote the textbook in the first
place. There was never any intelligent
agent acting as author or editor. (51) Selection
is only possible to the extent that there is residual excess population. "Fitness
is
actually the real trait that natural selection always acts upon, and this
very fundamental trait is actually very poorly inherited." (59) Environmental factors are much more
important than genetic factors. Genetic
selection works. My career in science
involved use of artificial selection as a plant breeder. But both natural and artificial selection
have very limited ranges of operation.
(63) "Selection works on the genic level, but fails at the
genomic level." (64) As a
population we carry many trillions of deleterious mutations. (71)
They will continue to accumulate and the species must degenerate.
(72) The mutations of nucleotides
result in gradual erosion of information.
(73) "If we start with a
very long and complex written message (i.e. an encyclopedia), and we start to
introduce typographical errors, most of the individual errors will only have
an extremely trivial effect on the total message. Individually, they are truly
insignificant. But if this process is
not halted, eventually the message will become corrupted, and it will
eventually be completely lost." (73) "While
selection is essential for slowing down degeneration, no form of selection
can actually halt it." (83) "A
very weak signal is easily destroyed by any amount of noise." (90) "In the big picture, noise will
consistently outweigh the effects of individual nucleotides. This is a primary reason why selection
works on the level of the gene, but fails on the level of the genome."
(90) "Total fitness combines all the different types of noise from all
the different aspects of the individual." (91) "Low heritability means that selecting
away bad phenotypes does very little to actually eliminate bad
genotypes." (91) For
example, "consider seeds from a cottonwood tree. Some seeds will land on fertile ground
ideal for growth, with abundant moisture, few weeds, etc. But most seeds will land on placers that
are too dry, too wet, too many weeds, too much shade, too many people,
etc. The result will be great diversity
in the health and vigor of the resulting trees, and huge differences in their
survival and reproduction. But almost
all of this 'natural selection for the fittest', will really only be
selection of the luckiest - not the
genetically superior." (91) "If
noise routinely over-rides selection, then this makes long-term evolution
impossible
." (99) "If
the genome is actually degenerating, it is bad news for the long-term future
of the human race. It is also bad news
for evolutionary theory. If
mutation/selection cannot preserve
the information already within the genome, it is difficult to imagine how it
could have created all that
information in the first place! We
cannot rationally speak of genome-building when there is a net loss of
information every generation!" (105-6) In The Descent of Man, Darwin contended
for superior races, ushering in an era of racism working its way out in
Hitler's Germany. Prior to WWII many
nations had government-directed eugenics programs that force sterilized the
'unfit,' and promoted abortion/fertility-control for the underclasses. The eugenic's vision is an insidious
delusion. (116-17) "Eugenics has from its inception been
a racist concept, and has always been driven by the Primary Axiom. Eugenics is not genetically sound. Furthermore, it is tightly linked with
authoritarian government, elitist philosophy, suppression of personal rights,
and violation of human dignity." (118)
"In
plant genetic improvement, when a species is easily propagated clonally,
clonal selection provides the surest and fastest way to improve a
population. Just choose the best
individuals, and multiply! It is about
that simple." (118) However,
within any clonal line, even the best sub-clones will accumulate mutations
over time. Even selection does not
stop the decline. All change is
downward. Each cell division adds
mutations. Net information always
declines. "Cloned animals
routinely display immediate and severe genetic damage. It is as if they are "pre-aged."
(119) "New
mutations occur in every cell, at the rate of roughly one mutation every cell
division. Therefore, essentially every
single cell in our body is unique. For
these reasons every human clone will always be inferior to the mature 'source
individual' from which they were cloned.
Such a clone will in a sense be pre-aged - having the original
mutational load of the source individual, plus the mutational load that has
accumulated during that person's growth and aging." "There are powerful moral, social, and
genetic arguments against cloning." (120) Genetic
entropy, the degeneration of the genome: we experience it on a personal
level; we see it all around us; and it is why we are all individually in the
process of dying. (121) Can
mutation/selection create a new gene?
No. "To create a new
function, we will need to select for our first beneficial mutation, but we
can only define that new nucleotide's value in relation to its
neighbors. Yet to create any new
function, we are going to have to be changing most of those neighbors also! We create a circular path for ourselves -
we will keep destroying the 'context' we are trying to build upon. This problem of the fundamental
inter-relationship of nucleotides is called epistasis. True epistasis
is essentially infinitely complex, and virtually impossible to analyze, which
is why geneticists have always conveniently ignored it. Such bewildering complexity is exactly why
language (including genetic language) can never be the product of chance, but
requires intelligent design. The
genome is literally a book, written literally in a language, and short
sequences are literally sentences.
Having random letters fall into place to make a single meaningful
sentence, by accident, is numerically not feasible. The same is true for any functional strings
of nucleotides.
A pre-existing 'concept' is required as a
framework upon which a sentence or a functional sequence must be built. Such a concept can only pre-exist within
the 'mind of the author".
Starting from the very first mutation, we have a fundamental problem -
even in trying to define what our first desired beneficial mutation should
be!" (124-25) Man and
chimp differ at roughly 150 million nucleotide positions, which are
attributed to at least 40 million hypothetical mutations. (130) "Most
DNA sequences are poly-functional, and so must also be
poly-constrained." The DNA has
meaning on several levels. "For
example, imagine a sentence which has a very specific message in its normal
form, but has an equally coherent message when read backwards. Now let's suppose that it also has a third
message when reading every other letter, and a fourth message when a simple
encryption program is used to translate it.
Such a message would be poly-functional and poly-constrained. We know that misspelling in a normal
sentence will not normally improve the message - but at least this would be possible. However, a poly-constrained message is
fascinating, in that it cannot be improved - it can only degenerate." (131) "Changing anything seems to potentially change everything!" (133) The
author provides several additional arguments along separate lines, but the
conclusion is the same. Even though we
know that 'micro-evolution' (adaptive selection) does happen, the genome must
have been designed and could not have evolved. "When we see adaptive selection occurring,
we are usually witnessing segregation and recombination of useful variants of
genes and gene components - which were designed to segregate and recombine in
the first place. We are not usually
seeing the result of random mutations - which are consistently
deleterious." (139-40) "Mutational
entropy appears to be so strong within large genomes that selection can not
reverse it.
I have termed this fundamental problem Genetic Entropy. Genetic Entropy is not a starting axiomatic
position - rather it is a logical conclusion derived from careful analysis of
how selection really operates." (144) "Selection
occurs on the level of the whole organism, and cannot stop the loss of
information due to mutation, which is immeasurably complex, and is happening
on the molecular level. It is like
trying to fix a computer with a hammer - the microscopic complexity of the
computer makes the hammer largely irrelevant.
Likewise, the microscopic complexity of genomic mutation makes
selection on the level of the whole individual largely irrelevant."
(144) "If
the Primary Axiom is wrong, then our basic understanding of life history is
also wrong. If the genome is
degenerating, then our species is not evolving, but is essentially
'aging.'" There appears to be a
close parallel between the aging of a species and the aging of an
individual. Both seem to involve the
progressive accumulation of mutations."
"Genetic damage results in aging, and aging shortens
lifespan. This is true for the
individual and for the population.
Logically we should conclude that if all of this is true, then at some
time in the past - there must have been a time when there was less genetic
damage in the genome, and thus longer lives, and less deleterious effects
from inbreeding. (147) "Information
theory clearly indicates that information and information systems arise only
by intelligence, and are only preserved by intelligence." (150) "Information's fundamental nature is
to degenerate, and this reality is reflected all around us
. The reason our information systems do not degenerate
even more rapidly is because of our elaborate, intelligently-designed systems
to stabilize and preserve information." (151) Postlude
- There is a hope. 153 ff. |
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