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BIOLOGY: AN OLD PERSPECTIVE |
The currently predominant scientific vision of the
world originated in the "scientific revolution" begun in the XVI and
XVII centuries by Copernicus, Galileo and Newton's theories. The technical and
economic boom that produced the subsequent industrial revolution drove science
towards a mechanistic, utilitarian approach to nature, the purpose of which was
(and still is) to predict and control the studied phenomena.
Until then, the close contact
with nature inherent to Western and other cultures' lifestyles had engendered
an "ecological" vision of "Mother Earth". Scientific
perception of the world was aimed at understanding the meaning of
natural phenomena (in a religious or philosophical context) rather than trying
to dominate them.
New knowledge from physics
and ecology has highlighted the failure (and peril) of man's attempt to control
nature, and suggests a need to return to an "old way of looking" at
the world.
BIOLOGY:
AN OLD PERSPECTIVE
Students of science history
will not be surprised to find that "objective" scientific
observations can easily be a reflection of the observer's own mental framework.
This culturally determined "way of thinking" derives from the
combination of more or less accidental historical circumstances that shape the
beliefs of a specific society at a given time, along with personal circumstances
shaped by the subject's own experience and training. It is what the science
philosopher Thomas Kuhn called the "Paradigm", which is not a
scientific theory or hypothesis, but a way of looking at the world which is
influenced by scientific observation and experience, and also by the observer's
cultural prejudice.
Scientific interpretation of
nature, especially of the origin and relationships between living beings, is
perhaps one the disciplines that has most clearly evidenced this "cultural
dependency", most probably due to an unconscious, a posteriori
attempt by the scientist to find or rather justify man's place in nature in
accordance with the most profound, deeply rooted beliefs of his social and
cultural context.
Not even the greatest minds
of history have freed themselves from this trap. Aristotle's hierarchical
concept of the animal world and different peoples can be explained by the fact
that he was a member of the aristocracy and hence a slave owner. The theory of
cataclysms and successive creations used by Cuvier to explain the obvious
sudden changes in the fauna between geological strata had clear religious
connotations in addition to the influence of his contemporary revolutionary
spirit. There are hundreds of similar examples familiar to us, and thousands
more...
So, what about the present
concept of the living world?
The theory of evolution, the
central idea to the description of the origin and relationships amongst living
beings and between them and their environment, is apparently solidly based on
Darwin's 1869 work, "The Origin of the Species by Natural Selection".
The influence of the predominant contemporary economic and social theories by
Malthus and Spencer is obvious. Thus, if we at least admit the possibility that
certain cultural influences or prejudices about the scientific perspective on
the world, a brief reference to the current context is also pertinent. From an
historical perspective, the present situation is none other than the
culmination, and perhaps the start of the crisis, of the economic and social
model that began at the time of Darwin's theory. The consolidation and
sophistication of the two models have certain similarities. When the free
market economy was expanding at the start of this century, the empirical basis
provided by the mathematical theory of population genetics for the description
and prediction of biological variation facilitated the reorganisation and
consolidation of the Darwinian theory in academic circles. Under the name of
the Synthetic Theory, it claims that the micro-evolutionary processes of random
mutation that generate variability and random genetic drift are harnessed by
natural selection or intraspecific competition, thereby acting as the driving
force for change and evolution.
Let us try to withdraw from
the time context (to do so from the cultural environment is harder) and try to
contextualise the present paradigm. Although the synthetic theory has
sufficient explanatory capacity and potential for experimental verification to
explain the observable variability in present living beings, it
is much less appropriate for explaining how this point has been reached. Even
Darwin himself was unconvinced, writing, "Why, if the species have
descended from other species through undetectably minute graduations, do we not
see everywhere innumerable forms of transition? Why is the whole of Nature not
in confusion instead of the species, as we see them, being well defined?"
If his theory was true
"The number of intermediate and transitory stages between all living and
extinct species must have been inconceivably great." In other words, there
should be evidence of the transition between the different animal phyla (fish,
amphibians, reptiles, birds, mammals), although this is obviously not the case.
Moreover, the larger the amount of data available, the greater the evidence of
the lack of a gradual transition between groups (Fig. 1). Darwin himself
acknowledged that this was "the most obvious and serious objection that
could be raised against my theory."
As in so many other cases,
however, the disciples turn out to be more radical defenders of the master's
theory than their master himself: the modern defenders of natural selection
(the clearly predominant body of thought in the scientific world) claim that by
working gradually through intraspecific competition on random mutations,
natural selection is not only an acceptable explanation of present biological
variation, but is moreover the only possible mechanism to explain it.
One extremely belligerent
(and apparently successful) exponent of this attitude, the prestigious
zoologist R. Dawkins (1), finds no difficulty in explaining the appearance of
new complex structures in living creatures as the result of the accumulation of
random mutations shaped by natural selection. He does not hesitate to use this
mechanism to describe the appearance of the eye, for example, in spite of its
complex structure and cerebral connections and its controversial evolution:
"O ne per cent vision is better than total blindness, 6% is better than
5%, and so on upwards in a gradual, continuous
series." This simplistic way of
"explaining" the appearance of complex new organs and structures is
quite common in texts on evolution, despite its obvious weakness, since
otherwise they could not be explained in terms of natural selection acting
gradually on random mutations as a mechanism for change.
Nevertheless, the lack of any
creative role by this process can even be seen in the experiments that purport
to confirm it: the famous example of "industrial melanism" in the
peppered moth (Fig. 2) shows that natural selection can only explain variations
within the limits of a certain species. In 1973, the French biologist Pierre
Grassé (L'Evolution du Vivant" wrote that proof of Darwinian evolution
"...Is merely the observation of demographic factors, local fluctuations
of genotypes and of geographic distributions. The observed species have often
remained practically unchanged for hundreds of years!" This phenomenon is
familiar to palaeontologists. It has led S.J. Gould and N. Eldredge (2) to
formulate the theory of "punctuated equilibrium", according to which
most species appear suddenly in the fossil records and remain with few or no
changes until their disappearance or sudden transformation into a different
species that arrives fully formed (Fig. 3).
Proof of this (previously
described by Cuvier in the XVIII century) should lead us to think that the way
one species is transformed into another might indicate that there is something
other than the gradual change mechanism postulated by the synthetic theory. On
the contrary, however, Gould and Eldredge's interpretation does not leave the
slightest room for such a possibility. They claim that these new species are
formed quickly "in a geological context", but always through the
action of natural selection on gradual changes.
Evidence for this phenomenon
might have prompted Darwin to propose an alternative mechanism to explain these
sudden changes. But it is too late. The Paradigm is too well entrenched.
One perhaps simple but
nevertheless pertinent example can be found in modern cities. For the average
citizen of industrialised countries, bound to the tough working conditions of a
competitive society based on production and consumption, every individual is a
potential competitor, customer or employee (this may also be extrapolated to
international relations). This is precisely the "scientific" vision
set out by Dawkins (3) in his "selfish gene" theory, based of course
on the "objective" observation of relations between organisms, which
is supported by a considerable number of biologists.
Of course this is an extreme
example of neo-Darwinian tendencies, and has obvious ideological connotations.
Not all scientists accept such radical socio-biological views. The majority,
however, when subjected to the paradigm of natural selection as the driving
force of change and competition as its main resource, try to justify the
growing body of evidence for genetic variability in organisms, increasingly
inexplicable in terms of natural selection, by pointing to a growing proportion
of neutral mutations and random microevolutionary phenomena (4).
THE
"SAMURAI" BIOLOGISTS
The apparent inability to
accept that the fundamental problem, the origin of these divergent and often
contradictory explanations, might be the cultural approach used in the to
analysis, does not prevent this phenomenon from arising in scientists from
other cultures.
One of the best-known
Japanese biologists is Mooto Kimura. His "neutralist" theory of
evolution is based on "orthodox" criteria and methods, (i.e.,
acceptable to western science), as he is an expert in population genetics.
Nevertheless, his conclusions appear to question the Darwinian model. He claims
that the majority of DNA mutations are neutral, i.e., they do not give the
organism a real advantage in the "struggle for survival". Naturally,
as a specialist in population genetics, he has been able to test the action of
natural selection, although he does not believe that it has the
"creative" importance attributed to it by Darwinists.
Another highly prestigious
Japanese biologist, practically unknown in the West, is less influenced by the
"orthodox" methodology. Kinji Imanishi (University of Kyoto), who has
been studying evolution since 1941, claims that Darwinism errs in
over-emphasising the individual, when in fact the group is the real entity.
Nature encourages continuity, mutual relationships and stability. He believes
that the basic concept is "coexistence" and not the Darwinian
"competition principle". Change is progressive and co-ordinated in
cells, organisms and in populations. In evolution, all individuals of a species
change at the same time when the moment arrives. It is a "maturing"
process, not a random mechanical change in a few genes.
The most interesting feature
of this vision, which is the closest match to the fossil record evidence, is
that the author acknowledges its cultural component- an attitude hard to
imagine in "orthodox" scientists: "Darwin lives in the West and
Imanishi in the East", he writes. Western culture exalts individualism;
life is competition, while Eastern philosophy/religion is impregnated with a
sense of solidarity, the preponderance of the society over the individual.
In "Darwin amongst the
Samurai" (Mundo Científico, vol.6, nº 4), the French biologist Pierre
Thuillier discusses Imanishi's theory: "Hence, the anti-Darwinist theory
can freely develop a "poetic vision" that has the basic advantage of
appealing to the Japanese public. Ultimately, the harmonious nature described
by Imanishi plays a "compensatory" role. When the Japanese experience
harsh competition in their everyday lives, the evolutionary utopia offered to
them gives them a reason to believe in a better world."
Apart from this questionable
interpretation of Japanese society (a lot could be said about how such
competition is organised, its social integration and its results), it is
striking that he justifies the origin of a scientific theory on both its
cultural context and the "tastes" of its audience. The author does
not, however, suggest a similar phenomenon in the "Western" theory,
as from his cultural perspective, "It is proven that intraspecific
competition is manifested in 90% of the cases studied". He goes on,
"Have Kimura and Imanishi been carried away , so to speak, by the
same cultural wave?"
Thuillier claims that,
"Imanishi brings us back to an old, still unresolved problem: the
integration of Western science [i.e., Science] by an outside
culture." ( the present author's italics). Outside cultures
(outside what?), however, may have "useful" aspects. Thuillier
discusses Werner Heisenberg's opinion about the Japanese physicists Tomonaga
and Yukawa: "For example, the great contribution by Japan to quantum
mechanics since the last war may indicate a certain relationship between
traditional Eastern philosophical ideas and the philosophical contents of the quantum
theory. It may be easier to adapt to the quantum concept of reality when one
has not yet been subjected to the simplistic materialism that still reigns in
Europe in the final decades of this century." For Thuillier, this cultural
way of looking at matter (the Paradigm) seems valid when describing some
aspects of reality but not others, as he concludes: "The difference is
that Yukawa turned to physics and in 1949 was awarded the Nobel Prize, while
Imanishi, who continued to reject the "bellicose philosophy of
neo-Darwinian evolution, chose to challenge it with anti-western
evolutionism."
It thus seems that matter,reality,
differs according to one's scientific discipline.... Or perhaps it might be
that the differences depend on who is doing the studying.
Let us briefly return to
quantum physicists who seem to have disengaged themselves from their cultural
context to some extent (their obvious advantage is that their study matter is
abstract tand thus avoids socio-economic nuances). What is the "philosophical
component" of their theory that suggests such kinship with Asian
traditions?
Put simply (with apologies to
Dr. Heisenberg), there are three outstanding aspects: put in
"accessible" terms, the first is that subatomic particles, the ultimate
components of matter, are not "individual entities" (particles in a
material sense), but only exist in terms of their relationship with the rest.
The second is that energy/matter, produced by these "systems of
particles" is organised into discontinuous "quanta" from the
level of elementary particles up to the Universe. These systems are formed by
lower level systems that interact in such a way that "the whole is more
than the sum of its parts", called "Holons" by the physicist A.
Koestler.
The third and perhaps hardest
feature to "visualise" is that the elementary particles, electrons,
have the dual quality of being particle and wave at the same time- opposing and
at the same time complementary conditions, and thus their essence cannot be described
at a given moment other than in terms of probability.
QUANTUM
NATURE
These three concepts all
differ from the mechanistic, materialist view of reality describe by Heiseberg,
but are accepted by the scientific community as if they were scientifically
demonstrable facts, (i.e., empirically and experimentally), in spite of being
hard to "visualise" materially. If, however, we focus on our
"visual field", an intermediate space between subatomic particles and
the Universe, we might have a "direct experience". Can these concepts
be applied to the living world by applying the freedom of the physicist's mind?
Let us consider the first two
points. Although the trend or inevitable necessity in biology for
specialisation leads to the study of very restricted aspects of living beings
(at times to a surprising extent), it seems clear that the concept of the
"independent organism" has little real value. Ecology explains that
living beings organise themselves through intense exchanges with their surroundings,
which in turn are organised as a dynamic, highly integrated ecosystem. The sum
of these ecosystems also makes up system of living and non-living forms at
different levels, amongst which there are interrelationships and
interdependencies. Finally, the whole biosphere constitutes an enormous
dynamic, self-regulating ecosystem.
At lower levels, the
organisms themselves are open systems composed of units that are grouped into
organs that work in co-ordination with others, and which at the same time are
formed by cells- highly complex systems that include mechanisms to transform
energy, information and regulation networks, the generation of internal and
external structures.... All of these levels have the common quality that the
whole is more than the sum of its parts, none of which can survive if not in
harmony with the rest. Not even genes can be regarded as individual entities,
since their activity (and existence) depends on the co-ordinated interaction of
many regulatory proteins, histones, RNA and even other individual or grouped
genes that must be synchronised. In other words, biological processes seen in
overall terms are in effect systems that integrate different levels and work in
harmony, as a whole according to the "eastern-quantum" perspective.
Of course the relationships between each component could be described more
prosaically (more "objectively" in our perspective) in terms of struggle
or competition: a way of describing biological phenomena such as the
selection of males for mating, food gathering, the immune processes and even
the mechanisms for genetic regulation, which can be defined in terms of
"competition between histones and the transcription factors" (5).
This interpretation of struggle or competition may, however, have an element of
observer input which, when the specific fact is analysed, might understate its
significance or function in the more global context of its relational system
and the final results.
BACTERIA:
"QUANTAL LIFE"
One spectacular example of
such a dual interpretation is a phenomenon that I consider crucial to
biological processes- the origin of the eukaryotic cell and hence the first
component systems of living beings.
The mystery of the formation
of the first cell, a complex and exquisitely interweaving of processes that is
so hard to explain from an orthodox perspective (6) as a result of gradual,
more or less random chemical processes, has been explained by Margulis and
Sagan so soundly that it is considered to be one of the few scientifically
proven evolutionary processes. The insertion of a Prochoron bacterium,
or aerobic bacteria like Paracoccus or Rhodopseudomonas , into
another (Fig. 4) seems clearly (morphologically and functionally) to have been
the origin of chloroplasts and mitochondria, essential organelles of eukaryotic
cells. It can also be verified by deciphering and comparing the DNA of these
organelles with the above-mentioned bacteria, revealing surprising similarities
that are indicative of a faithful conservation of these DNA sequences from
their origin. The authors also claim to have observed the symbiotic origin of
eukaryotic cell organelles in the derivation of cellular microtubules from
spirochaetes.
The orthodox interpretation
of this extraordinary process is that it is a case of phagocytosis (i.e., one
"bacteria industry" or "bacteria bank" devouring or
assimilating another) conferring a selective advantage , or a case of
parasitism (by which one benefits at the other's expense).
From a different perspective,
i.e., from outside the paradigm of competition as the driving force of
evolution, it can be described as the integration or co-operation of two or
more systems, the result of which something more than the sum of its
constituent parts: Bacteria are systems, totalities, what physicists call
Holons and, although seemingly strange, this integrity ensures their sudden
appearance, given that totalities, like quanta in physics, cannot appear
gradually. This different perspective might encourage a search for the meaning
within the phenomenon- its teleological content (which is not in itself
negative or ascientific, but merely a possibility), and allow the deduction or
induction of the results or consequences of such co-operation.
This concept (or something
similar) has been used in a rigorous study of the phenomenon by Margulis, who
defends bacteria against their "excessively maligned" traditional
role ("What is Life? Simon and Schuster, 1995) as merely the source of
illness, overlooking their vital role in the origin of eukaryotic cells and a
wide variety of important functions within the dynamic relationship between the
"living" and "non-living" worlds. It is generally accepted
that in the origins, the extraction of carbon dioxide from the primitive atmosphere
and the generation of an atmosphere with a high oxygen content was largely due
to the activity of photosynthetic bacteria and subsequently of unicellular
algae, their first descendants.
Moreover, present-day
bacterial functions may differ greatly from the pathological character usually
ascribed to them. Some fix nitrogen in poor soils and facilitate plant life
which would otherwise be impossible, others produce fermentation and make
substances assimilable and useful to complex organisms which could not be
exploited without such prior activity. Some do their work in herbivore
intestines, some in humans, while others transform elements that are toxic to
other organisms such as nitrogen, sulphur and carbon compounds into organic
matter that can be absorbed by plants.
The neo-Darwinian explanation
of these necessary processes for life might "simply" be that
the bacteria have adapted to a lifestyle that coincidentally is useful for life
itself. However, there is further process (guided mutation) which disturbs the
defenders of the orthodox theory, as it may well "waken the ghosts of
Lamarckian evolution", although it might also shed light on the matter. It
has been found (8) that when certain bacteria are presented with a food source
they cannot use, they mutate (in this case two independent mutations which
alone would be of no use) that facilitate the assimilation. The probability of
this simultaneous event happening spontaneously is virtually nil. It is thus a
response to the environmental conditions, and hence a post-adaptive mutation.
In other words, as Margulis
indicates, they are not merely pathogenic agents but a basic component of life.
They obviously have a pathogenic character, but one might consider that this is
so when an external phenomenon disrupts the harmony (or, if that sounds too
"eastern" or unscientific, the balance) by which biological
phenomena occur in nature. In an ecological sense, is there a "bad
guy" in the food chain?
THE
VIRUS: MESSENGER OF DEATH - MESSENGER OF LIFE?
Speaking of "bad
guys", there are other "critters" that do not seem to fit into
this "harmonious" vision of the terrestrial ecosystem. Judging by the
social repercussions echoed in the scientific and general media, the virus has
apparently become the worst enemy of the human race.
In scientific terms, the way
they invade cells, their self-organisational ability, their origin and place in
nature, etc., are still a mystery despite their detailed study and our
knowledge of many of their genetic sequences (Fig. 5).
These beings on the boundary
between the living and non-living worlds have no real existence except within
other organisms. Outside, they cannot be regarded as "live"
organisms. They are simply a DNA or RNA molecule wrapped in a protein capsule
of a sometimes surprisingly geometric shape. The way that these
"inert" bodies inject their genetic material into the host cell is
also surprising, but more astonishing still is that with their genetic material
they feed in the enzymatic machinery that makes it possible to cut and merge
the host cell's DNA with their own, entering the host cell where they can stay
inactive or begin to translate their own genetic information. In some cases
this information allows new viruses to be constructed using the cellular
machinery until the cell is destroyed and others are infected. This is their
pathological quality. Others, however, merely feed their genetic information
into the rest of the cellular DNA (Fig. 6).
The biological significance
of this integration process may be familiar to the reader: it is a means by
which two genetic units (two systems) can combine into a single larger unit.
How does this fit into the evolutionary context? This feature makes the virus
worthy of consideration as a potential mechanism for the input of complex DNA
sequences into animal and plant genomes. By taking the unconventional path,
i.e., instead of trying to fit the data to a preconceived body of ideas that
explain evolution, we shall look at the data afresh and then see what plan they
suggest.
Variable amounts of DNA known
as "endogenous viruses" have been found in animal and plant genomes.
Most of the different types are thought to be derived from exogenous viruses
that infected the species in the past and have become endogenous by insertion
into germ cells. Thousands of sequences of viral origin are being discovered
that actively participate in the function of distinct tissues. Some of these
sequences can be regarded as true genetic fossils; "ancient"
proviruses that have undergone multiple mutation although they can still be
linked to some present retroviruses. Others occur in the form of mobile or transposable
elements (TE)- DNA sequences capable of moving and inserting themselves or
their copies into new locations in the genome.
The meaning of
the presence and activity of all these viral elements in animal and plant
genomes can be deduced from their effects. Through their reinsertion, the
mobile elements can provoke chromosomal reorganisation and, above all, changes
in gene expression and regulation, with important evolutionary consequences. A
retrotransponson has been described that is responsible for the
modification-amplification of the expression of the genes involved in amylase
secretion. In mammals it is only secreted in the pancreas, but in humans it is
also secreted by the salivary lands, thus extending the range of food that can
be ingested- a clear adaptive advantage. Other retrotransposons are involved in
the regulation of genes linked to hystocompatibility (9), and to the expression
in tissues of human, mammal, invertebrate and plant alphaglobines (10, 11, 12,
13).
This explains the lack of
correspondence in attempts to link the morphological evolution of closely
related species to the rates of amino acid change in proteins: it may have
taken place primarily by means of changes in the regulation of genetic activity
rather than through changes in amino acid sequences.
Recent discoveries are even more
spectacular (and informative) about the activity of endogenous viruses: in some
cases, endogenous retroviruses can carry genes from the somatic to the germ
line. In a recent study, Rothenfluh demonstrates the existence of a genetic
transmission mechanism of the acquired immunological memory of lymphocytes to
the germ line, thus constituting a strictly Lamarckian mechanism. In other
cases, the retroviral sequences are expressed directly: nearly 1% of the
10,5000 completely known genetic sequences expressed in 37 animal tissues
correspond to endogenous retroviruses and are expressed as a constituent part
of the brain, placenta, embryo, lung, etc. (Genome Directory, Sept. 1995).
Finally, another important
form of activity from an evolutionary-mythological perspective has been
discovered in HIV-1 retroviral antigens, expressed in human placenta
trophoblast cells. This important task contributes to the morphological
differentiation of these cells.
Data from a well-studied organism
in developmental genetics can provide clues to the obvious evolutionary
significance of this phenomenon, as well as in terms of the control of cell
proliferation: 15 retroviral sequences have been identified in Drosphila
embryos, whose purpose is the spatial and temporal control of the
development of different tissues (12).
An expanding body of this
type of information can be found in recent (and doubtlessly future) scientific
publications on molecular biology, virology, genetics, etc.
A VERY
OLD NEW MODEL
Returning to the previous
theme, what might this type of information mean from an evolutionary
perspective? In the above context, it provides a reasonable answer to several
unresolved problems for the Synthetic Theory:
Firstly, it demonstrates the
existence of a mechanism by which the new genetic information may be fed
into genomes by the integration of a complete system- a mechanism that is much
more plausible than the mutation-disorganisation of a closely interconnected cellular
system. Secondly, it may explain the appearance of these new sequences
(Goldsmith's "macromutations, se Box 2), in a sufficient number of
individuals to facilitate their survival as a species. And thirdly, the sudden
changes associated with this phenomenon would prove the existence of the
saltationist phenomena observed in the fossil record.
Defenders of the conventional
evolution theory would not hesitate to reject these three general aspects, but
if we avoid the theoretical or philosophical implications and focus on the
rationalist, Cartesian methodology -the only one in our cultural context of any
use for a scientific analysis of reality, we can seek possible proof for these
three suppositions.
Abundant molecular
information solidly backs the first aspect: one significant example is the
extremely conservative nature of ancestral sequences that can be traced
from bacteria up to higher organisms. They can be followed from the regulatory
sequences of genetic activity such as the TBP (the "universal
protein"), through cellular proteins, up to cellular structures such as
microtubules. This astonishing pattern is often mentioned but rarely given any
importance. However, it would obviously not happen if evolution were to happen by
small random mutations that had diversified the DNA from the bacterial origin
up to the present organisms.
This is not a mere hypothesis
or interpretation. The changes and chronology of genetic sequences by
integration have recently been documented: sequence analysis of genes related
to the expression of amylase in human salivary glands suggests that the
retrotransposon responsible for amplifying its expression may have been
inserted 45 million years ago (the palaeontologically established point of
separation between prosimians and anthropods (9). Furthermore, the
retrotransponsible element L-1.2, the first to be identified in the human DNA
in chromosome 22, has been located in the same place in chimpanzees and
gorillas (15), suggesting that it has been at the same genome location for at
least 6 million years.
Spectacular results have been
obtained recently in the study of large tax, although they do not lead to any
evolutionary interpretation as they are inexplicable from the official
paradigm. A considerable difference between the retroviral
"populations" of reptiles and those of birds and mammals has been
demonstrated (16). Does this have an explanation from our perspective?
Other, less demonstrable but
no less indicative proof can be added to this list. Several aspects of
embryonic development have been interpreted lucidly by Charline and Devilliers
(17) in an evolutionary context. They claim that the biological variation of
the Synthetic Theory, which states that genes are treated in calculations of
evolutionary genetics as being independent from each other, "is an
unsustainable reductionist position. Not all genetic combinations are actually
feasible. There is a small number of genotype combinations for each
organisational plan." The genome now appears to be "a system
organised into hierarchical and interconnected functional levels." The
gene ceases to be a free agent , and becomes "a member of a society
whose correction mechanisms restrict its potential for variation within a range
of the possible and the impossible". The stability of these paths,
however, would not imply that they were unalterable. natural selection has
clearly worked in living beings, but only on specific characters in the final
stages of embryonic development, whose inflexibility diminishes as the initial
"almost immutable" stages such as those that determine the overall
organisation are superseded by phases that are more "open" to minor
changes.
The action of retroviral
sequences involved in cellular differentiation is perfectly plausible in
this embryonic mechanics of "hierarchised and interconnected functional
levels", as this is a means of feeding into a closely knit system the
sequences (the system) necessary for the expression of a new tissue (or even an
organ) with a large number of equally interconnected processes that this
requires.
Strange as it may seem, the
experts in ontolonogenetic development are not surprised. They conclude their
article by asking, "Have these intermediate forms, so often lost and
missed, always existed? Are they not in many cases simply the fruit of
imagination impregnated by the necessity of continuous series?" The
conclusion from the rigorous analysis of embryonic processes and their role in
evolutionary change is clear: "The discontinuity (of the fossil record)
may not be contingent- linked to gaps in the record-, but rather fundamental,
which can be attributed the evolutionary mechanics."
What is really disturbing
about this more than plausible evolutionary mechanism, however, is that it
inevitably implies that the viral sequences which most probably have been
involved in the evolution process must have contained a priori complex
sequences with a biologically consistent expression. Naturally one may think
that their current expression may have been acquired "randomly" after
their insertion, but certain anatomic facts help to choose one of the two
alternatives.
"Mosaic evolution",
normally used as an example of gradual change (Fig. 7), is usually explained
very vaguely in palaeontology texts. Often used examples are the
"mammal-like reptiles" from the Permian and Archaeopterix (268 and
150 M.y.a., respectively). However, these examples not only give the impression
of a gradual change, but also of large-scale reorganisations that involve
simultaneously interrelated sets of tissues and organs (for a deeper analysis,
see "Lamarck y los Mensajeros" by the present author).
Perhaps the most important
information in this sense stems from a much more surprising and controversial
evolutionary process. "Adaptive convergence" has been defined from
the neo-Darwinian perspective as proof "of the incredible ability of
natural selection to collect good designs" (1), i.e., incredible
similarities produced by random (and individual) mutations that survive and
dominate as a result of similar selection pressure. This claim, however, is
based more on a firm belief than on scientifically proven facts. How can these
random, independent mutations explain the surprisingly close resemblance in the
general morphology of species from different sub-classes of mammals that
branched in the Early Jurassic (200 M. y.a.) and have evolved separately since
then, e.g., marsupials and placentals? Morphologically similar versions of
wolves, cats, moles, flying squirrels, anteaters have arisen in Australia (Fig.
8). Is the same morphology necessary to move across the ground and feed? Is it
imposed directly by habitat, which on the other hand is not absolutely
identical on every continent? Why could the randomly produced organisational
plan not have led to the existence of a chickephant, for example?
The present or past existence
of complex genetic sequences that led to these "general designs" may
seem mysterious, but on clear reflection, it would be even more fantastic if
they had been reached via processes that are accepted as logical by the
conventional evolution theory. Whatever the case, for orientation purposes we
may recall a mammalian order in the early Palaeocene (66 M.y.a.), the Creodonts,
which left no "direct" descendants, i.e., they bear no relation to
their present counterparts although their remains prove that their anatomies
"resembled" ferrets, cats, wolverines or dogs. Similar phenomena have
also been observed in insects and plants.
Taken together, these
arguments probably cannot even establish the plausibility of this process, so
we shall make a final effort using the arisal of the eye, an incredibly complex
and efficient structure with simultaneous essential neuronal complements, which
has been the subject of fierce debate. Some sequences even belong to
retroelements involved in the formation and function of the crystalline lens
(18). The existence and structural similarity of the eye in many
phylogenetically distinct lines has obliged acceptance of the surprising idea
that because it is an efficient model, it may have arisen several times in the
(fantastic) random process of evolution. Pausing for thought along the
rationalist method, this multiple development would be statistically equivalent
to the probability of a gorilla (or in its absence an action movie star)
bashing away at random at a typewriter and producing Don Quixote several times
over. In spite of the range of "environment pressures" , however, it
is surprising to see the close resemblance of, for example, vertebrate and
octopus eyes.
All of these data lead us to
propose an alternative concept or model which Darwin himself would probably
have accepted as a clarification of his doubts. It is an old model that shares
the concepts of Cuvier and Lamarck who, incidentally, can be found at the
deepest roots of Darwin's work.
In effect, "intermediate
stages" cannot be seen in the fossil record, nor even in living species,
because they probably never existed. We have also seen that the inheritance of
acquired genetic characteristics is possible, and even the horizontal
transmission of these genetic sequences amongst species in different phyla is
possible (19).
Furthermore, we would also
accept the evidence of data that shed light on an old debate: whether selection
equals (or implies) adaptation but not evolution. The truth is in
fact completely the opposite. Moreover, even if one accepts the
"non-creative" but conservationist role of natural selection, it is
still impossible to adduce a fundamental role to all-powerful chance, in the
light of two striking facts that have been disputed since the onset of the
Darwinian theory: the response of organisms to natural selection and the
perfect adaptations to the environmental conditions (in many cases so
sophisticated that Darwinian biologists tend to use Lamarckian expressions,
"The branchii grow longer or increase their area in order to
extract oxygen more efficiently in deep water", etc.). The complexity of
processes involving many adaptations makes their appearance extremely difficult
to justify as a random action of small individual mutations and their
subsequent slow expansion through the population by means of mechanisms
proposed in population genetics.
There are, however,
mechanisms that seem to justify "mutations" as a response to the
environment, making these two phenomena more reasonable.
Recently (20) non-pathogenic
viruses have been found to undergo multiple mutations that render them virulent
as a consequence of dietary deficiency in the host. The Coxsackievirus is a
family of two types- A and B. Their infection of humans induces pathologies in
only 10% of cases, some of which have been well documented experimentally. In
mice, for example, the CVB3 and CBV4 viruses produce inflammations of the
myocardia and pancreas respectively.
When mice were inoculated
with a non-viral strain of Coxsackievirus 3 (CV3/O), a selenium-deficient diet
was found to produce a single, extremely virulent type of CVA3 in different
mice 10 days after inoculation. Their genomes revealed that they had undergone
6 nucleotide changes at the same 6 positions. Studies of different nucleotide
changes in the CVB3 genome confirm that there is a small number of changes
linked to this virulent trait, i.e., not just any change will do.
The paper interprets this
obvious response to environmental stress through several independent mutations
(reminiscent of what we have seen in bacteria) in a way that is driven by the obligation
(perhaps unwitting) to not transgress the orthodox interpretation, i.e., the
paradigm. It claims that there were multiple random mutations and what was
found in the different mice was the result of selection that had led the different
viruses to precisely the same mutations.
This interpretation is hard
to defend. It is a further example of the way that scientists "tend to see
what they have been trained to see, and cease to see what they know
should not be there" (Kuhn). Subjecting the data to the paradigm of
competition as the driving force of change impedes one's view of the obvious,
and leads to interpretations that are at times so complicated that they verge
on the miraculous in explaining much simpler phenomena (albeit no less
mysterious to our mental schemes- Fig. 9).
The aggressive vision of
nature criticised by Imanishi sometimes turns scientific language into
something reminiscent of military terminology. We are at war against the virus,
at war against bacteria, against insects... But perhaps, as has often been the
case in human history, we have provoked them beforehand. The difference is that
in this case, there might be no winners.
However, by distancing
ourselves from this viewpoint, well-reasoned explanations can be found to the
evolutionary predicaments arising from such strained and often contradictory
interpretations.
Viral integration provides a
mechanism to explain the saltationist phenomena (obvious in the fossil record),
speciation and even rapid response to the environment. Evidence of
post-adaptive mutations in virus (also seen in bacteria and yeast) and the
ability of the virus to integrate and then leave the genomes of living beings,
explains horizontal transmission between different species, and even between
different phyla.
The latest discoveries of
these surprising phenomena suggest that the whole concept of nature may have to
be reworked. It is not a matter of starting over again (the methodology and
specialisation have amply proven their efficiency), but rather changing the way
of interpreting the information which, as we have seen, lead to different
answers. And these answers in turn make us ask new questions:
Might this response by the
virus to environment stress explain the existence of sources of "emerging
viruses" in populations subjected by the economic system to harsh misery
and famine? When humanity lived in harmony with nature, we must have lived in a
reasonable balance with micro-organisms (which does not mean that we were free
of illness), and the permanent famine we see now at different points of the
planet were then only sporadic events.
Are "scientific"
manipulation such as the production of vaccines using ape blood, or
xerotransplants (using the tissue of other animals) perhaps feeding specific
viral sequences into humans from animals that might have terrible
repercussions?
Are treatments using broad
spectrum antiretroviruses on AIDS (or simply seropositive) patients damaging
retroviral sequences that normally work in different organs, accelerating their
death?
And finally, might
"oncogenes" not simply be sequences of a viral origin, whose purpose
is to work during embryonic growth to produce the cellular differentiation and
proliferation of a specific tissue (an interesting clue is the extreme cellular
specificity of the virus)? Might tumour proliferation be "simply" an
activity of these sequences at an unfortunate moment, either due to
environmental factors, of renowned influence in viral activation such as
radiation, foreign chemical substances or dietary habits or deficiencies?(21).
The answer to these questions
(and their practical consequences) does not imply that the "Paradigm"
needs to be questioned, but it does highlight the need for a change of attitude
in scientific and philosophical vision of natural phenomena. There may well be
a great deal of truth in the harmonious concept proposed by Imanishi: the ideas
of concerted change and maturing (Lamarck's trend towards complexity). This
also indicates that a process may be underway that is still beyond the scope of
our scientific and technical ability which are, in fact, a result of our way of
thinking. Because what is definitely beyond doubt is the enormous danger
(especially for humanity) of senseless attempts to manipulate biological
processes which we really do not understand.
We do not dominate or
control nature, although we are convinced that we do. We can only attack it,
and we cannot predict its response, the way it will regain its balance.
Unfortunately, this is not a metaphor but a fact that "ignorant
natives" the world over have discovered and suffered: our science, our
culture with its reductionist and mercantile attitude has focused too much on
studying trees and the profit that can be made from them, which is precisely
what has prevented us from discovering the beauty and harmony of the forest.
BIBLIOGRAPHY
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2. Elredge, N. & Gould, S.J. 1972. "Models in
Paleobiology". T.J.M. Schopf (ed.) W.M. Freeman.
3. Dawkins, R. 1975. "The selfish gene". Oxford University
Press.
4. Charlesworth, B.; Sniegowski, P. & Stpan, W. 1994. "The
evolutionary dynamics of repetitive DNA in eukaryots". Nature. Vol. 371,
215-220.
5. Chouard, T. & Yaniv, M. 1994. "El control de la expresión de los
genes". Mundo Científico. Vol. 4. Nº
149.
6. Gesteland, R.F. & Atkins, J.F. 1993. "The RNA World".
Cold Spring Harbor Laboratory Press.
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Sagan, D. 1985. "El origen de las células eucariotas". Mundo
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8. Rennie, J. 1993. "Los nuevos giros del ADN". Investigación y
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9. Robins, D. & Samuelson, L. 1993. En "Transposable Elements
and Evolution". McDonald, J. (ed). Kluwer.
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expression of retrovirus-like transposons during Drosophila melanogaster
embryogenesis". Genetical Research. 64: 3.
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Elements and Evolution". McDonald, J. (ed). Kluwer.
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"Expresion of endogenous HIV-1 crossreactive antigens within normal
extravillous trophoblast cells". Journal of Reproductive Inmunology, 28,
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Kazazian, M.M.Jr. 1991. "Isolation of the L1 gene responsible for a
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18. Brosius, J. & Gould, S.J. 1992. "On 'genenomenclature': a comprehensive
(and respectful) taxonomy for pseudogenes and other 'junk DNA'". Proc.
Nat. Acad. Sci. 89: 10706-10710.
19. García, J.;
Bayascas, J.R.; Marfany, G.; Muñoz, A.; Casali, A.; Baguna, J. & Salo, E.
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Box 1:
The selfish gene hypothesis
or theory can be regarded as the philosophical culmination of liberal economic
Darwinism taken to a mechanistic, reductionist extreme.
At present it is widely
accepted by many biologists, especially geneticists and biochemists, who regard
it as a good model to explain the variability of genetic sequences in different
animal and plant genomes.
The theory claims that the
real unit of evolution is neither the species nor the individual, but the
individual gene or DNA segment which is virtually eternal once it has gained
"supremacy" amongst populations. Organisms are only a vehicle, a
survival machine for the genes.
According to Dawkins, all
animal behaviour is guided by the following principle: "For every survival
machine, every other survival machine is an obstacle to overcome or a
resource to be exploited".
Criticism of this warped
vision of nature includes the fact that this theory has become part of the
British neo-Nazi party ideology. But it is not necessary to seek out radical
ideological connotations. The theory is actually the basic idea underlying the
business and social relations of our "free market economy".
Box 2
In the 1940's, the German
geneticist R. Goldshmidt was the first scientist to propose a genetic
explanation for the saltationist phenomena found in the fossil record. He found
that ordinary and isolated mutations in Drosophila were too small to be
extrapolated to macroevolution. There had to be "macromutations",
i.e., mutations with an instantaneous effect that had a great influence on the
viability of the individuals. The reaction by "orthodox" scientists
was cruel. They claimed that the results of these "macromutations",
which they sarcastically called "monsters with a future" or
"hopeless monsters" would have no partners to mate with, and would
thus have no place in evolution.
Nevertheless, viral
integration not only makes "macromutations" feasible, but also the
simultaneous appearance of a considerable number of "monsters with a
future".
Figure legends
Figure 1
The comparison of basic
components in today's major taxa (DNA, RNA, cellular proteins and even
hormones") provides increasing support for the existence of these gaps in
the fossil record. The phylogenetic relationships deduced from them are
"lateral kinship", not descent.
Figure 2
"Industrial
melanism" of the peppered moth is a classic example of direct observation
of natural selection, and is commonly used in texts on evolution. When
light-barked birch trees and building facades in England were darkened by
industrial pollution at the start of the century, the dark moths became more
abundant than the pale forms because predatory birds found them harder to see.
When the pollution was reduced, the pale varieties became predominant again,
i.e., only the proportions of each colour changed.
Figure 3
The presence of "living
fossils" is usually attributed to the stability of the marine habitat, but
this stability cannot explain the sudden disappearances and transformations
that are seen in both the marine and terrestrial environment.
Figure 4
Research is bringing to light
a growing number of bacteria which enter another and actively participate in
their life cycle. The truly astonishing aspect is that this cannot be described
as a case of phagocytosis or parasitism. It is real symbiosis which is
transmitted by inheritance in many cases, i.e., the symbiotic association is
maintained during reproduction.
Figure 5
The usual explanation for the
origin of the virus is a fragmentation of genetic material, which
"somehow" escaped from the original cell. This explanation might be
comforting to a mechanistic mind, but neither its strange properties nor its
appearance are so. the illustration shows a T-type phage. The electron
microscope photograph shows a l -type phage "landing" on a bacteria.
While those who have studied biology are familiar with the image and know (?)
its origin, the traditionalists try to convince their "profane"
audience that it is "merely" a piece of DNA that "escaped"
from a cell.
Figure 6
The biological cycle of the
virus, first seen in bacteria and then in eukaryotic cells, has two
alternatives: in the lytic phase (A), the virus injects a DNA or RNA molecule
which takes on a circular form and replicates by a rotation that generates a
long DNA chain with several copies of viral genes. Each copy controls the
synthesis and assembly of the proteins in the virus capsule using cellular
material. In an hour, the host cell lyses (self-destructs), freeing some 100
viruses which can infect others. In other cases, depending on currently poorly
known conditions, the lysogenic phase (B) arises. The viral DNA enters a point
of the cellular DNA (specific to each virus) where it codifies its own genetic
information and replicated in each cell division. Under these conditions, the
latent virus ("protovirus") can be maintained indefinitely, although
it sustains its ability to produce a lytic cycle, multiplying itself anew. This
process can be induced experimentally by exposing the cell to UV or X rays, or
chemical compounds.
Once the cell is infected,
the RNA or retro-viruses are transcribed to DNA by means of an enzyme: reverse
transcription.
While the DNA has an extremely stable behaviour (it can reproduce more
than 100 million times without a single nucleotide error in its chains), RNA viruses
change (mutate) some 100,000 times faster than DNA viruses. The basic cause is
that reverse transcription "does not know how to correct" the errors
in the copy, and hence often feed "imprecise" nucleotides into the
transcribed DNA. Considering the extreme stability of the DNA (heightened in
the cell by the extraordinary mechanism of
enzima.
| ¿PENSAMIENTO ÚNICO O AUSENCIA DE PENSAMIENTO? |
|
SOBRE
EL ORIGEN
DEL HOMBRE |
|
HACIA
UNA NUEVA
BIOLOGIA |
|
TEORÍA
SINTÉTICA: CRISIS Y REVOLUCIÓN |
|
SYNTHETIC
THEORY:
CRISIS AND REVOLUTION |
|
LOS CIEGOS
Y EL ELEFANTE |
|
LA FUNCIÓN
DE LOS VIRUS
EN LA EVOLUCIÓN |
|
LAS
"SORPRESAS"
DEL GENOMA |
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NUEVA BIOLOGÍA
PARA UNA NUEVA SOCIEDAD |
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ADN, LA MOLÉCULA MILAGROSA |