First Published: July 1, 2007
Nutrition and Health Volume: 19 issue: 1-2, page(s): 103-132
Issue published: July 1, 2007
Corresponding Author: David E. Marsh
T: +44/0 2087411998
This short history of evolutionary thought during the last few centuries describes how some of our foremost thinkers have debated – and still do – the precise mechanisms at the roots of evolutionary change.
Commentators frequently contradicted themselves, as well as each other. The popularity of Christian fundamentalism waned following the World Wars. Eventually the rug was pulled from beneath it – till a more recent reaction.
Amidst all this babble coming from numerous towers of Babel over centuries, we failed to see Charles Darwin as the great environmentalist: who said environmental conditions, whilst working hand in glove with natural selection, constituted the more important 'law.'
A bird's eye view of 18th and 19th century evolutionary thought is considered against the climate of those times (politics, industrial revolution, trade, religious expansionism, etc). Darwinism superseded Lamarckism helped by the neo-Darwinism of Weismann, higher mathematics, population genetics – the 'Modern Synthesis' of 1935 – culminating in the discovery of the double helix by Watson, Crick et al, assuring us of the correctness of 'primacy of DNA theory'.
Stimulation and challenge is currently fuelled by exciting nascent knowledge of epigenetic variations and Cairnsian 'adaptive mutations'. The work of Marcus Pembrey and Barry Keverne tracking human and animal variation back generationally describing how 'genomic imprinting' causes reversible heritable change from slight variations in the chromosomes of parents, grandparents, great-grandparents and parents to be.
The purpose of this thesis is to put forward a new theme proposed neither by Lamarck or Darwin. We stand on the threshold of the first paradigm change for 150 years.
Reversible-generational-change, Epigenetics, Environmentally-induced-variation, Adaptive-mutations, Nutrition, Substrate, Genomic-imprinting, Neo-Lamarckian-medicine, Neo-Darwinism, Evolution
Tracing the history of evolutionary thought throughout the last few centuries it is curious how often the old chestnuts frequently crop up, nature versus nature, Darwinism versus Lamarckism, Creationism and Intelligent Design versus evolution, epigenetics and environment versus natural selection.
Author for correspondence: firstname.lastname@example.org – www.davidmarsh.org.uk +44/0 2087411998
Corrections (errata, apologia) of version published version Nutrition and Health, Vol 19 1&2 Jan 2008).
It’s surprising what a champion of the environment Darwin was, and indeed still is, for his thoughts on what he termed ‘conditions of existence’. These are now remarkably prescient with new knowledge describing how ‘epigenetic variation’ affects the behaviour or expression of the genome, the genetic material. Epigenetic variations result from environmental influences such as substrate, nutrition, stress and emotions, specific chemicals – including pollutants or addictive drugs etc. They are instigated by changed environmental chemistry, of maternal environment particularly, traits which can for example be passed down generationally, affecting shape, form or function along familiar lines (thus ‘familial’ diseases – and the opposite: fit, active, long-lived healthy lines).
Darwin said there were ‘two great engines’ thrusting evolution forward: natural selection and ‘conditions of existence’. His opinion on which of the two was the most influential itself evolves over his lifetime.
• “In all cases there are two factors, the nature of the organism, which is much the more important of the two, and the nature of the conditions. The direct action of changed conditions leads to definite or indefinite results. In the latter case the organisation seems to become plastic, and we have much fluctuating variability. In the former case the nature of the organism is such that it yields readily, when subjected to certain conditions, and all, or nearly all the individuals become modified in the same way (Origin, 6th ed).
• “I am convinced that Natural Selection has been the most important, but not the exclusive, means of modification. “…” But the fact of variations … occurring much more frequently under domestication than under nature...lead to the conclusion that variability is generally related to the conditions of life to which each species has been exposed during successive generations.” (6th Ed.) Then Darwin appears to contradict earlier ideas –
• … changed conditions of life are of the highest importance in causing variability, both by acting directly on the organisation, and indirectly by affecting the reproductive system … (author’s italics)” and “it is generally acknowledged that all organic beings have been formed on two great laws – ‘Unity of Type’ and the ‘Conditions of Existence’ … in fact the law of the ‘Conditions of Existence’ is the higher law, as it includes, through the inheritance of former variations and adaptations, that of Unity of Type”4 (Origin, Chapters 5 & 6, 6th edition).
But Darwin’s brilliance in championing the environment working side by side quite happily within natural selection over millennia was to become a victim of the ultra rightwing Weismann, who dismissed Darwin’s belief in the supreme importance of environmental pressures helping to power the theory of natural selection.
From the ‘primacy of DNA theory’ grew the belief that natural selection was a force ‘sufficient unto itself’. From then on Darwin’s considerations of ‘conditions’ took an increasingly back seat, finally just ‘providing a genepool’ from which selection then operates and the ‘gene for everything’ theory we have today – which there may be but what is the relationship of that gene or its controlling gene or genes to new environmental pressures and challenges presented by new epochs of evolution? [Does the gene include the switches – or are they external to it?]
Epigenetics is beginning to show how short sighted was this ‘gene for everything’ theory, examples being:
• The average height in the UK during the last century increased approximately 0.4 inches per decade. Such change is too fast for the process of selection – without reference to new substrates – new agricultural and dietary fashions and the industrialisation of our soil and food chain.
• The long chain polyunsaturated omega 3 fatty acid docosahexaenoic acid (DHA) affects 107 genes in infant rats. This is evolutionary biochemistry. We need not doubt that this is not also happening in human populations.
• Recent research shows babies born to mothers who ate more fish (omega 3 DHA) during pregnancy at age 8 outperformed a group of several thousand children followed since 1991 (see Hibbeln, below).
It is said that Charles Darwin died ‘almost a Lamarckian’. It is true that his first tutor at Edinburgh was a Lamarckian. It is also true when it is said of Darwin that ‘he spent most of life trying to work out the exact mechanism whereby ‘conditions of existence’ – (Darwin’s phrase, we now say environment, substrate or nutrition) cause variation in species. In many ways this mirrors Lamarck, who also spent most of his life devoted to working out the same conundrum.
Today, although epigenetics has been around (under that name) for 50 years, it’s gaining attention since the human genome map was completed a few years ago. Then it was revealed that we have far fewer genes than we expected, and that controller genes – switching on or off of different genes or blocks of genes depending on conditions – could be considerably more important than previously recognised.
The phenomenon of environmental variation had been an accepted fact of evolution way back before the turn of the last century, when it was known as ‘environmentally induced variation’. However, because such generational change often reverted to previous forms, it was not considered important. A clear example of this is seen in the fossil record in trilobites with 9 sets of legs, then 11, then 13, after thousands of years suddenly reverting to 9 pairs of legs again. This points to a previous richness of the creature’s environment which had enabled it to grow more sets of legs, suddenly feeling the pinch of shortage of building blocks, causing it to downsize: an example of what Darwin termed ‘plasticity’ of variation.
Darwin’s contradictions or the evolutions of his thought become apparent only with the benefit of 150 years hindsight. During the last century and a half it was not so clear. One can see the prescient vision of Darwin, his superb and intricate studies and analyses of both the minutiae and cascades of creatures, his cranial descriptive brilliance was perhaps to be mirrored later by August Weismann. They were both way ahead of their time(s): there were few, if any, of sheer intellectual capacity to keep up with them. And so it came to pass that both men succeeded in changing man’s thoughts, creating a new paradigm which most of us have grown up accepting.
Now the scene is about to change once more. Fascinatingly it is Darwin’s original thought processes on environmental effect that shine when considered with knowledge currently emerging in the epigenetic arena. For now we consider not just the initial effect of substrate or nutrition on chromosomal variation, but what happens in further generations, when the initial epigenetic changes continue in following generations and we come across the crossword puzzle presented by genomic imprinting.
The history of the theory of evolution is currently being brought alive with the realisation that we are living within a period of paradigm change in evolutionary theory. Not every person in his or her lifetime experiences the excitement of such philosophical or scientific upheavals.
Recent discoveries concerning various environmental pressures affecting the genome and succeeding generations have brought this subject, known as epigenetics, alive.
Philosopher of science Thomas Kuhn popularised the terms ‘paradigm’ and ‘paradigm shift’ in his book ‘The Structure of Scientific Revolutions’ 1962.(1) Its publication was a landmark event in the sociology of knowledge. Before Kuhn the term had been used only within grammatical discourse. Since 1962 it has become synonymous with patterns of scientific belief systems and the influences and conditions under which they change.
Galileo was imprisoned for his beliefs that the earth went round the sun, although later released from prison after disowning them, he spent the remainder of his days under house arrest, hardly a fitting prize for one who gained the reputation of being ‘father of modern physics’. Christianity made the gods and goddesses of Rome redundant.
Charles Darwin was vilified by the establishment for his beliefs – together with Alfred Russell Wallace – particularly by the Church, which he knew he would be … and why he delayed publication for 20 years before being rumbled by Wallace. (This junior partner, who had arrived at the same conclusions as Darwin after a much shorter period of study and reflection, and then sent his paper to Darwin for his criticism).
Jean-Baptiste Lamarck was not the first European to explain the unfolding of life but, in his book ‘Philosophie Zoologique’, he was the first to popularise a theory of evolution (this was unusual, for Lamarck was a biologist).
Lamarck’s first draft (1797) was coincidental with publication by Charles Darwin’s grandfather, Erasmus Darwin, whose long and studiously boring poem Zoonomia echoed Lamarck’s beliefs. It is said they did not know each other – however, the Darwin family were conversant with the French language – so they would have been up to date with developments across the Channel.
Lamarck’s later versions appeared in 1803 and 1809.(2) This should come as no surprise for the evolutionary soil had earlier been sown with the thoughts of Walter Johann Goethe and Jean-Jacques Rousseau (achiever of a doubtful reputation during the French Revolution) who were influential during the 18th century.
Concentrating on Lamarck and those who came later, let it be said that he was a man of huge importance. Although usurped by Wallace and Darwin 50 years later, he influenced half the world for 50 years. Lamarck’s beliefs were basically that God, when wanting a change (of species) changed the environment, so the creatures living in such changing conditions had to change (‘need’, le besoin), and change they did.
It is tragic that he died impoverished and was buried in a pauper’s grave. It is the author’s belief that he will recover his reputation as the ‘Father of Evolution’ which title he enjoyed before being done down by M. le Baron George Cuvier and for decades later by European academics.
Very much the aristocrat, Cuvier was not only a Creationist, but was also a Catastrophist – which school of thought believed that every so often God wiped out all existing life and started things going all over again. He was the equal opposite of Lamarck who was not of landed gentry, but made his way in the world by his own brilliance.
It is curious that Cuvier, an establishment figure, holding opposite ideas to Lamarck was chosen to write the Eulogy at Lamarck’s funeral. However, Cuvier himself died before delivering the eulogy which was read by someone else. Cuvier’s (or the reader of the eulogy’s) dirty tricks department provided a sly change in his eulogy, suggesting that Lamarck had said that ‘species changed from wishing or willing themselves to change (le desire)’, rather than needing to change (le besoin). It would no doubt have caused poor Jean-Baptiste to turn in his grave.
A year after returning home from his historic voyage around the world aboard H.M.S. Beagle Darwin came across Thomas Malthus’ “Essay on the Principle of Population”.3 Having been impressed and influenced by the work of Sir Charles Lyell, who’s book “The Principles of Geology” he read whilst on board, on the movements of continents and the evolution of geology he had been primed for this extraordinary work which was to give him the final clue to his own conundrum.
“October 1938, read Malthus’ “Essay on the Principle of Population”, being well prepared to appreciate the struggle for existence... it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of a new species. Here then I had at last a theory by which to work.” (The Autobiography, Life and Letters).
Darwin read Malthus “for amusement” however the effect was considerable. The simple point argued in Malthus’ essay is that all organic species multiply in a geometric ratio 3…9…27… etc., whilst the food on which they depend for their existence can only, in the most optimistic terms, increase in a arithmetical ratio 2...4...16...etc…
Darwin, having become used to the idea of the movement within geology through absorbing Lyell’s work, was now helped to see the progression of movement within the environment itself and the growth of populations of organic beings living within them. He saw how all living-systems have mechanisms whereby they produce vast numbers of seeds or eggs which far exceed the survival rate. He saw the squeeze put on life in nature and how there was a constant struggle for available resources.
From this vital clue he began to see how any species with even the slightest adaptive advantage over competing neighbours would be the survivors. He termed this phenomenon natural selection, meaning that the whole process appeared to have no observable causative mechanism other than struggle and competition working in association with external conditions, producing progressions which nature threw up from time to time.
Thus it was natural, by “chance” and fortuitous. Fortuitous in positive change; evolution, but disastrous in the negative; extinction. Darwin explained he did not actually mean by “chance”, but by this expression meant ‘caused by something that men at that time were ignorant of…’ This mechanism was an entirely new concept to science. Although, as Darwin himself pointed out in his “historical sketch”, he was not alone in feeling that there was some such mechanism listing over thirty other naturalists, biologists and observers who had by the late 1850’s begun to think in the same terms.
Darwin sat on his new idea for nearly twenty years before letting it become public knowledge, feeling it too revolutionary for the general good. His hand was forced by Alfred Russell Wallace who had come to similar conclusions through his work in the East Indies. Wallace sent Darwin his own ideas on “Selection” in 1858 and in that same year they read joint papers to the Linnaean Society; immediately after which Darwin hastily produced an “abstract” of the plot he had been hatching over the previous two decades and published the ‘Origin of Species by Means of Natural Selection’ in the following year. (On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. 1st Edition, 1859).(4)
Having been accepted by the greater part of the scientific community within a few years of publication of the “Origin”, natural selection was to be triumphant for the following twenty years. Whilst not unchallenged, selection became the accepted theory of evolution. It was after Darwin’s death in 1882 that the theory of natural selection started coming under increasingly heavy attack.
The first serious challengers were the neo-Lamarckians. Excluded from the new version of the old Lamarckism were several ghosts of the old era, the Vital Force, the Supreme Author and the belief, or tendency toward belief, that some purposeful (teleological) ends were pre-ordained; that arch-factor which had been so successfully eliminated by Darwin.
Neo-Lamarckians, pioneered largely by American scientists, maintained Lamarck’s original inner driving force but lost the connection with environment again due to no mechanism being isolated. Evolution was seen to be proceeding in a gradual and regular tempo with progress being reflected in the development of the individual embryo. The theory, which had a strong following amongst American scientists, had its peak popularity during the 1890s.
It was Professor August Weismann, from the University of Freiburg, who played the next opposing move. It was in 1885 that he published his theory of the “continuity of the germ-plasm”; an equal and opposite idea to Darwin’s concept of ‘pangenesis’, which was a seemingly wild hypothesis proposing that environmental changes became registered in the germ-plasm – which in those far-off days was unprovable. Weismann however insisted on the absolute isolation of the germ-plasm from ‘somatoplasm’ or other parts of the body. (Germ plasm … the physical basis of inheritance … germ-cells are the reproductive cells, the opposite to somatic cell; primitive male or female element). What he managed to persuade the scientific world of his day to believe was that the reproductive or sexual cells carrying what we know now as DNA, bearing what we now know as genes, lived a bunkerlike existence, being shielded from all environmental and somatoplasmic pressures with few exceptions – radioactivity being one and certain specified chemicals another.(6)
Weismann argued this absolute gulf with splendidly convincing rhetoric. Whilst the body gave of itself, and actually created the germ- plasm, fed it, nurtured it and acted as its vehicle, it could never affect the germ-plasm itself. Thus, in its splendid isolation, there could be nothing that could affect the structure of the genetic mechanism via the body tissue. This move is thought by some to have been a check to the direction that, in his later years, Darwin was moving toward, veering uncomfortably close to the ideas that Lamarck had had at the beginning of the century.
Indeed Darwin, having been so utterly condemning of Lamarck, had taken his ideas on the effects of habit, or use and disuse (without giving any credit) was now seen to be playing into the hands of the opposing camp of the old school naturalists and organic evolutionists possibly posing political, even theological, threats.
But Weismann’s insistence on the insulation of the genetic mechanism from any actions of the body put an end, for the time being, to this drift. His erudite argument, which was for his time scientifically remarkable, strongly re-enforced the focus of attention on the internal, into the heart of the hereditary mechanism. Darwin had first taken the focus of attention into the organism, lessening respect for the chemistry and quality of nutrition (in those days little was known about nutrition).
Weismann strongly re-enforced those ideas and was also responsible for the creation of neo-Darwinism. He went blind in later life turning to theory from experimental work and formulated his theory of Germinal Selection, according to which variation was “directed by competition for nourishment among ‘character-units’ of the germ-plasm” (genes had still not yet been discovered). The theory was that by this mechanism it was possible for any change to move in the direction favoured by selection!
This early suggestion of evolution’s involvement with food is quite stunning in view of contemporary research work, which makes it look very much as if the opposite could be happening. Note: Danish botanist Wilhelm Johannsen coined the word “gene” in 1909 (The word gene was derived from De Vries’ term pangen, itself a derivative of the word pangenesis which Darwin (1868) had coined).Through his ‘advanced’ thinking Weismann removed even that aspect of the original Darwinism that brought the environment into consideration.
He argued a powerful case for the ‘all-sufficiency of natural selection” (3) – The title of Weismann’s article replying to Herbert Spencer’s defence of Lamarckism, 1893 – an early example of the blind leading the blind.
Mendel had originally published his paper in 1865 but it was born into a shadow cast by the worldwide excitement of Darwin’s success.(7) The paper was ignored and lay dormant for thirty-five years before its significance was discovered. The re-discovery of Mendel’s important paper in 1900 had given rise to other new schools of thought, which were initially to challenge the increasingly shunned Darwinism.
In fact it would have saved Darwin himself a lot of headaches had he realised Mendel’s discovery. For what was generally believed before this time was that the characteristics of the parents blended, and after a few generations, would become lost in obscurity.
Mendel’s work showed that whilst certain characters might appear to be lost they were still there but being carried as recessive genes. Then, when there was a fortuitous cross with another of the species, also carrying similar recessives the character would show up again. Darwin and others had put these phenomena down to atavism, or reversion to characters of the grand or great-grand parent. Mendel therefore explained the quantitative aspects of the hereditary mechanism. Mendel was indeed important but his was a theory of hereditary mechanism not a theory of evolution.
Mendel’s observations gave biologists the ammunition they needed to take this inward focus even further and later the molecular biologists would invert the gaze even more. Whilst most of the Darwin/ Lamarck argument hung on the inability of research to isolate the suspected, or expected, “Lamarckian Factor” another part of the thinking could have been centred, subconsciously or otherwise, on the implications of Lamarck’s “holistic” philosophy which might have re-raised the specter of religious domination that the evolutionists had been striving so hard, and so successfully, to avoid.
Furthermore, there would have been unpopular political implications which would have to be faced should the environment be discovered to be a formulating factor in evolutionary direction. These would have included more socialistic attitudes than were favoured in the eyes of those who supported the “survival of the fittest” theory which in a subtle way became an extension and refinement of the “right of might” argument.
The power of public opinion has always been an invisible agent in the evolution debate. It could well have been a reflection of the moods of the time in the 19th Century that the new theory of natural selection caught on in such a big way.
Natural selection’s attraction lay in two quite different areas. It was not only that what could easily be seen as an atheistic (although Darwin became agnostic) theory of evolution had arrived which had gained scientific acceptability but that there was then in existence a vast tidal wave of human emotion waiting to be ignited by just such the spark of new, refreshing and revolutionary thought that Darwin and Wallace provided.
For so many centuries the Church controlled not only peoples’ emotional lives but politics as well. Morals, the work ethic, education and decisions concerning war or peace were all made in the name of the Church. In other words, life was stuck in the harness of that thinking and the mood was of longing for change. There was as much talk in the 1860s of the new “enlightenment” as there was of the ‘New Age of Aquarius’ in the 1960s.
Despite the enthusiasm of such moods in its early days Darwinism was later to be severely challenged from within the scientific community itself. Roughly between the 1890s and the mid 1930s were decades filled with the emotional and passionate debate, during which period there were some who thought that Darwinism would not survive.
Although it is true that once again the blanket philosophy of (the new) Darwinism has become the subject of renewed criticism being felt, as it is by many, to be lacking in crucial aspects which might be connected to certain major problems that our own species face today.
Sir Julian Huxley coined the phrase “the Eclipse of Darwinism” in 1942 in his book “Evolution, The Modern Synthesis”. Peter J. Bowler in his book “The Eclipse of Darwinism”(8) describes how Darwin’s theory was indeed covered by a great shadow for more than thirty years and how it emerged into brilliance again after some of the most ferocious debates in the history of science.
It emerged refined, strengthened through suffering and the new discoveries of hereditary mechanistics, higher mathematics and population genetics, in a somewhat altered form. Thus the Neo-Darwinism of the “Modern Synthesis” in 1935.
Mention is made of public sentiment in evolutionary theory which could have been underestimated in the past. Indeed some of the strongest contenders amongst the alternative schools of evolutionary theory fell foul of such public feelings during the battle for control during the “Eclipse” as we shall later see.
So whilst we are considering largely a new scientific viewpoint we shall also be considering the evolving needs (including emotional and philosophical needs) of ordinary people. What Darwin managed to do so successfully was to take us not only from the grips of the Church but he also led us from purpose to chance and left a corresponding void in our culture. Life had been reduced to a series of chance events with survival of the fittest being the nearest we get to a purpose.
The application of higher mathematics to genetics, from around 1917 to the mid 1920s, led to another startling discovery. Based on the work of the statistician A. Fisher and J.B.S. Haldane, biologists in England and Sewell Wright in the United States, mathematical biology and genetics were successfully crossed giving birth to a new hybrid.
The new science of mathematical population genetics established itself by showing that when applying the principle of natural selection to theoretical models the effects of even small genetic changes at population level would result in the sort of overall change that Darwin himself was originally speaking of. Such changes could also be interpreted in Mendelian terms.
These discoveries were to unite Mendel’s ideas with Darwinism which began to emerge revived from its ‘eclipse’.
The excitement over these new discoveries was a reflection of the brilliance of Darwin’s foresight. That it took not only over seventy years but also the sophistication of higher mathematics for lesser mortals to come to similar conclusions was a significant step for the future emergence of the previously warring factions. But this stunningly accurate observation did not, even then, account for the actual cause or origin of diversity. This was pointed out by the geneticists. What Darwin was seeing was a cause and effect phenomenon, the effect of which he called selection.
The causal mechanism of the change was simply explained as being produced fortuitously by nature and therefore ‘natural’. Perhaps the most common objection to his theory was that whilst selection could be seen to account for the progression of the best-fitted to the environment (Darwin’s original term) it would not account for the production of the least-fitted.
For the other side of the coin of survival of the fittest was elimination or extinction of those organisms whose design did not match the demands of the environment and the struggle for existence. On these grounds selection could be doubted as the actual driving force.
But after Mendel’s “proof” by population genetics and its ensuing success as a theory of evolution the advances made in genetics and the understanding of hereditary mechanism were rapid, giving rise to the schools of molecular biology and genetic engineering we know today. They joined forces with the neo-Darwinism of Weismann recognizing the extraordinary power of natural selection but altering its role. Natural selection, they explain, works at population level on the “gene pool” of the species which is continuously being replenished by small changes. It is on these changes, Weismann convincingly argued, that selection then acts.
An explanation from C.C.Li, of the University of Chicago, in his book “Population Genetics” (1955) clarifies the situation described in this brief précis; “Gene mutations occur at random in nature at a certain low rate. The causes for mutation remain unknown (“spontaneous”) … The most important single conclusion in the genetic studies of Mendelian populations is that there is no one all important factor in evolution. The theory of isolation, of natural selection, of migration, of hybridisation, of mutation etc., none of which is adequate by itself, are combined into one comprehensive theory which includes the additional factor of chance. Evolutionary changes depend on the interplay and balance of all factors”.
This clearly reveals how all of the known factors must relate to the factor of chance and also highlights the omission of consideration of the chemistry of food and environment, not to mention the improbability that chance had anything to do with it, as Darwin himself had pointed out (Ch5, Origin, 6th ed. 1872).
The argument went on lengthily, often vehemently, until what became known as the “Modern Synthesis” emerged triumphantly in the late 1930s and early 1940s, when the mutation theory of Hugo de Vries teamed up with the schools of Biometry, Population Genetics and Molecular Biology in a new form of neo-Darwinism which had its origins in the theories of Weismann.
But for the first decade of the century these different schools had been actively engaged in opposing each other. The story of the process whereby the Modern Synthesis emerged has, as mentioned above, been meticulously related by Peter Bowler who comments; “It is certainly Conceivable that in the excitement generated by the synthesis of Mendelism and natural selection, some genuine problems may have been over-looked.
The few scientists who argued that apparently discredited ideas contained a kernel of truth that would help to solve these problems were ignored until recently. Some modern biologists now believe that an even broader synthesis of the various modes of change is possible. The potential of their new approach remains to be determined of course, and there are still many sceptics who believe that the challenge to modern Darwinism is unnecessary” (The Eclipse of Darwinism. Peter J. Bowler, 1983).
There have been numerous volumes written already on the subject of the experiments carried out in efforts to prove the ‘environmental unfolding’ theories of Lamarck. In the early part of this century there were literally hundreds of attempts. It is fascinating not only that none of them succeeded in convincing the scientific community of the efficacy of Lamarck’s ideas but that they collectively succeeded in failing to disprove them. The story is well told by Arthur Koestler in his book ‘The Case of the Midwife Toad’.(9) The main period of research activity came to an abrupt and abortive end, as if stunned by the tragic suicide of Paul Kammerer, a brilliant young zoologist from Vienna, who was perhaps the most valiant of all the ‘Lamarckian’ researchers. None-the-less, the discussions, scientific papers and further theorising continued as it has up to the present day. Now with the work of Australian Ted Steele interest has again been revived in laboratory research to evaluate those elusive factors amongst Lamarck’s ideas which no one yet has managed to denigrate entirely. Broadly speaking, these laboratory experiments were set up to show that: • environmental stimuli could effect change in living organisms.
• for the change to be passed on hereditarily to the offspring, and • that such change should be fixed genetically in a form of heredity which would follow the laws of variation and heredity as described by Mendel.
It is worth noting that at this time, the rigidly fixed type of heredity was the only type known and consequently the only type looked for.
The intense rhetoric of the previous century had argued, rightly or wrongly, that this was the only sort of change that could have a bearing on the long-term effects of evolution.
The argument came to hang on this 3rd clause; an example of what might be called the sophistication of evolution politics. In many of these so-called “Lamarckian” experiments change was achieved (following a change in “conditions”) and that change was passed on to the offspring. Where they all ‘failed’ was that reversion inevitably followed when the organisms were returned to their normal environment. Yet that is precisely what we would expect to happen! Because it wasn’t a (fixed) mutation, just environmentally induced variation, in grave error it wasn’t rated.
Broadly speaking these experiments, which sometimes took over ten years to conduct, were designed to demonstrate that characters could be modified by the environment and be passed on through the hereditary mechanism to the offspring.
If this could be proved under laboratory conditions and the results repeated elsewhere by other researchers in the standard manner of research procedure this would prove that there was a truth within Lamarck’s philosophy.
Therefore environmental and ecological considerations would thereafter have to be taken into account in evolutionary theory. Indeed it would be a factor as significant as natural selection, beside which mechanism the formative power of the environment would then take its seat, on the throne of evolutionary thought.
Everyone involved was aware of the sociological and political implications should such research prove positive, and that the stakes were high in this endeavour.
Kammerer’s work, briefly, included sea-squirts (Ciona intestinalis) with elongated siphons; the production of eyes in the blind cave-dwelling newt, Proteus; the production of nuptial-pads on the infamous Midwife Toad, Alytes obstreticans; and the most striking example perhaps being his experiments with Salamanders, whose mating habits, birth procedures and colouring he managed to change dramatically through getting them to breed in unusual environments. Black spotted salamanders became yellow and yellow spotted salamanders became black, with the change continuing in following generations, if his evidence is to be believed.
Kammerer’s genius at handling amphibians was one of the causes of his downfall for no-one else could persuade these delicate creatures to breed in captivity, despite several attempts, and so his results were never confirmed nor, again, disproved. The nuptial-pads of the last remaining specimen of the Midwife Toad, after the destruction and devastation of the First World War, were later found to have been injected with Indian ink. To this day no one knows the culprit. Was the whole story a fake? Was it a technician attempting to restore the fading specimen? Or was it deliberate sabotage?
The argument over the mid-wife toad had been vehement, the one pickled specimen which had remained after the war had been taken to England by Kammerer and inspected by the hand lenses and microscopes of the most eminent and critical biologists who were adamant that no evidence could contradict their Darwinian concepts. A year later the specimen was inspected in Vienna by Dr R.C. Noble and ink emerged from the nuptial pad!
It seems the fraud was too blatant and sufficiently out of character for it to have been done by Kammerer himself. But it is interesting that whilst in the West Kammerer’s reputation was ruined, leaving him accused of the unpardonable sin of faking his results. Pro-Lamarckian Russia (itself an extraordinary example of the inheritance of acquired characteristics, with a changed country in less than 70 years) continued to stand by him with their offer of a top job as director of a new research institute.
Although his life, work and reputation were destroyed by the specimen of the one surviving sample of the Midwife Toad, which had undoubtedly been nobbled by someone, he himself alleged that it was not the most significant example of his work. But it is a significant reflection of the hyper-emotional atmosphere surrounding the subject that the Midwife Toad was singled out for this fatal attack and that his other, more convincing work, was discredited in the blistering and concerted campaign conducted against him.
In the midst of the entire fracas, which coincided with an unhappy emotional period in his love-life, he walked up a lonely mountain track where he blew his brains out. It could also be argued that Kammerer was so successful that he was driven to a tragic and early death by unseemly gamesmanship from within the ranks of the scientific community.
Or is it possible there were some political protagonists involved in those dark days of the Twenties when Hitler’s fascist philosophy began to take a hold? Hitler had used Nietzsche’s philosophy, or rather a perversion of it, in his claim to lebensraum. There was a strong element of the survival of the fittest in his justification for his own monstrous and racial theories.
It is within the realms of possibility that there could have been a connection between the undoing of Kammerer and the fanatical protection of dogma and that the argument with the scientific community was a secondary factor. But the heat and viciousness of the controversy between the two scientific factions can be likened only to the most extreme religious animosity.
The tragedy that ensued could have some bearing on the fact that since Kammerer’s suicide there were no further efforts to confirm or invalidate his results. The whole affair was gruesome and sordid. The entire campaign drew the focus of the bitter argument onto the Midwife Toad. Had the case been conducted as in a court of law the other evidence of the defendant would no doubt have been presented and this consisted of his Salamander research, in which he had stage-managed extraordinary changes, which he considered his most impressive work. Experiments with the Sea Squirts had been repeated by other researchers but the smear campaign, centred solely around the miserable Midwife Toad, not only caused Kammerer’s ship to flounder but created a new problem in the Lamarckian arena; the possibility of the element of fraud.
Lamarckism had previously gained unpopularity as the social-Lamarckian model predicted the creation of hierarchies, which caused many Europeans concern.
Kammerer was not alone. Other experiments were set up to demonstrate the power of the environment to effect hereditary change; mice, rats, moths and many other species were subjected to various experiments. In the 1920s there was great excitement when previously fawn moths turned black in response to industrial pollution. Subsequent experiments repeated the results when fed on food with lead and manganese additives, (components of industrial pollution) demonstrating the power of chemicals to cause variation in the genetic mechanism, leading to a let-down when the pollution was cleared years later and the moths returned to their original colour.
Whilst these forty years of painstaking devotion failed to exonerate Lamarck they did not fail to disprove the validity of Weismann’s “isolation of the germ-plasm”. Where the “Lamarckian” experiments failed, even when hereditary change was produced in subsequent generations, they all reverted to their original form when reintroduced to their original surroundings.
Yet this rejection is a puzzle. If an attribute of a species is changed by the environment in a way that supports a Lamarckian influence surely a reversion to the original form when the environment is changed back to its original is precisely what one would predict on the basis of Lamarckian theory. It would be the condition under which reversion does not occur with restoration of the environment which would require an explanation.
We are reminded of the pigs that have escaped in Australia and become wild, or feral. They now resemble their original wild species in looks… and ferocity. No one would deny that natural selection had a part to play in this example of reversion but it was the environment that named the game.
We shall shortly see how reversion could be seen not as failure for the Lamarckian concept but as further evidence in favour of the formulating power of the environment.
Whilst the purpose of this thesis is to put forward a new theme, it is of particular interest with regard to these requirements that there is currently still the assumption that all genetic change that occurs must of necessity be this rigidly ‘fixed’ type of heredity which will run unchanged through countless generations.
That this ‘iron-clad’ form of genetic constitution exists is certainly not challenged by the author. What else can explain the countless species that have run true to form for millions of years, many of them still in an almost prehistoric form?
But this need not deny another type (or types) of genetic behaviour that might demonstrate a more malleable form of heredity? Otherwise, how do you explain the many examples of rapid change followed by periods of stability which, by comparison with the initial rate of change, were extraordinarily long? The case of the flies which suddenly appeared and never changed to this day, prompting Hoyle to suggest they came from outer space, is but one case of many.
The term Orthogenesis … literally meaning ‘straight-line evolution’ was introduced in 1893 by Wilhelm Haake11. It was an anti-Darwinian theory, essentially attempting to plug up some of the more obvious gaps in the concept of natural selection, such as the irregularities and discontinuities, such as the organisation of the phyla or the development of discreet lines, such as the carnivores or herbivores.
The view of its major populariser, Theodore Eimer, was of an evolution unfolding by means of a correlation between the individual’s growth and development processes and the environment, the ‘suspension’ of chemicals and atmospheric conditions on which its life depended. The thinking contained within the new theory was that evolution was directed by a purely internal force with organisms seemingly pre-programmed to vary in a particular direction.
Supporters were divided on whether this internal drive was stimulated by the environment or not; the majority thought not. Orthogenesis assumed the existence of large-scale trends which were regular, non-adaptive and gave rise to long patterns of linear evolution which were paralleled by groups of related forms that led ultimately to extinction.
Whole species like the giant reptiles or the little graptolites seemed predestined to go through a group lifecycle; species would collectively have a birth, youth, maturity and old age, proceeding through senility to extinction.
Most significant was the repudiation of Darwin’s claim that evolution always worked in an adaptive way. It was a common objection to Darwin’s scheme that everything that had ever evolved had done so by being best adapted to the challenges of the struggle for existence. There were, allegedly, so many examples of species which had obviously evolved in a non-adaptive way, such as the Irish Elk.
Carl Nageli had, in 1865, forced Darwin himself to concede that the widespread existence of non-adaptive characters was a major problem of his theory. They would frequently site the “evolutionary over-momentum” as witnessed in such species as the Elk, which had such large antlers that they were thought to be a factor leading to their extinction. Similarly, the sabre-toothed tiger had such huge tusks that it could not shut its mouth. It could be argued that the human brain might also fall into the same category; achieving such heights directed at the pursuit of technology and power that its unbalanced brilliance could, only too conceivably, lead to the extinction of the species. In the early days of orthogenetic theory the human species was carefully not brought into the discussion.
Eventually, and inevitably, it was. 1933 George W. Crile, of the USA, linked certain human disabilities, including peptic ulcer, to Orthogenesis. The theory from then on fell rapidly into disrepute. The tragedy of the Orthogenesists was that although they were partly motivated by the problems of the ‘extinctions’, they could not readily supply a reason for this seemingly unavoidable passage through degeneration and senility to the species’ disappearance.
Had they connected the limited supply of essential nutrients over a wide geographical area with the ever-increasing numbers of prominent species, which Malthus’ demography did, they would have found the link with the chemistry of the environment and with food.
In the 19th century Alpheus Hyatt had noticed similarity between senile and pathological forms. He realised that if an individual was exposed to unfavourable conditions it would develop a pathological structure. If a group were like-wise exposed, it would degenerate as a whole. Hyatt stressed the negative side of evolution and pointed out the human species also had senile traits. He opposed the emancipation of women on the grounds that it might lead to lack of differentiation between the sexes which was seen as a trait toward senility in animals.
It was thought that senility occurred when a group had run out of evolutionary steam and represented a retreat back to a stage from which the group had come. With this view, we might now ask: Is man becoming a savage again? Or is it change caused through the altered biochemistry of food and soil?
Later supporters of the hypothesis emphasised the orthogenetic trend need not have a predestined goal drawing it on. Anxious to cut off from Lamarck’s spiritual philosophy they pointed to the idea that it was a force within the organism which compelled it to develop in a certain way. This force would be the consequence of its physical or chemical constitution. But the odds were heavily against orthogenesis in the form it then took.
The philosophy, as a contender for the evolution stakes, came a cropper. The depressive atmosphere surrounding the new theory which led to extinction was too much for most to bear, to consider our own future in terms as bleak as the journey through group old age, senility and death.
It was worse than the most depressing aspects of Darwinism which were being objected to, neither was there any causal explanation to support the theory, although some of the commentators on orthogenesis came close to the ideas that we put forward.
What the Orthogenesists had was a valid criticism of Darwinian theory. Indeed the whole of orthogenesis arose because of genuine dissatisfaction with Darwinian inability to explain the discontinuities among other matters.
What they lacked was a biological mechanism for their lines, senility and extinction.
Faced with the elegant simplicity of the mechanism of natural selection any thesis without a mechanism itself could not be expected to last. Had they thought about the role of nutrition and nutritional quality they would have found the mechanism.
We know that the food of the carnivore has trapped it in a specific line and the exhaustion of essential nutrients can lead to species senility and finally extinction, whereas Man, as an omnivore, still has choice and mobility.
Richard Goldschmidt, as one of the few geneticists who seriously considered a place for orthogenesis, was unorthodox in his views. His particular interest lay in the orderliness of the growth process and believed we would see only the outcome of those mutations that produced an effect consistent with the existing conditions. This he thought would limit possible mutations to a single direction. He explains “The development of any primordium is closely interwoven with that of all other primordia and, therefore, a local change caused by a mutation affecting an early embryonic process … cannot lead to a viable result if the embryo is not able to carry out the proper regulations.
The selection of the direction in which genetic change may push the organism is therefore not left to the action of the environment upon the organism, but is controlled by the surroundings of the primordium in ontogeny, by the possibility of changing the ontogenic process without destroying the whole fabric of development … Thus what is called in a general way the mechanics of development will decide the direction of possible evolutionary changes. In many cases there will be only one direction. This is orthogenesis without Lamarckism, without mysticism, without selection of adult conditions”.
James D. Watson and Francis Crick, along with Rosalind Franklin and Maurice Wilkins, in 1953 discovered the structure of the DNA molecule for which they won the 1962 Nobel Prize. In describing the double helix they explained how information from the cell’s nucleus was translated via RNA to the cell.(13) Their work reinforced the concept of the ‘Primacy of DNA’ theory.
Watson went on to head the Cold Spring Harbor Laboratory raising major funds for basic science research and was noted for administrative successes and named to the head of the Human Genome Project.
These then were some of the arguments going on over the last 2 centuries and more.
Epigenetic change is modification of the genetic mechanism (DNA) by environmental influences, causing reversible generational change in shape, form or function, most commonly by changing genetic ‘expression’, or ‘behaviour’.
In the history of evolutionary theory ‘environmentally induced modification’ has been known and accepted from beyond the turn of the last century. But – as we have already seen – because it caused a form of change that was reversible it was not considered important.
Today, post-human genome map – which showed we have only roughly a third of the number of genes expected – with the greater knowledge in the subject, it is fast being realised that that viewpoint of scientists and naturalists of a century ago was misplaced.
Changing genetic expression means the same genome, the same shape or structure of DNA, behaving differently in response to changing conditions (or pressures) of the environment; sometimes referred to as ‘impact energies’.
Environmental pressures including chemical/substrate/nutritional/ hormonal/ emotional/atmospheric etc … appear able throw genetic switches on or off, enabling genes to make more of this protein and less of that depending on supply of available nutrient or substrate chemicals.
For those of us not well versed in the subject of epigenetics and imprinted genes, Dr Joanna Downer’s background information is useful. She says “There is far more to genetics than the sequence of building blocks in the DNA molecules that make up our genes and chromosomes. The “more” is known as epigenetics.20
“Epigenetics, literally “on” genes, refers to all modifications to genes other than changes in the DNA sequence itself. Epigenetic modifications include addition of molecules, like methyl groups, to the DNA backbone. Adding these groups changes the appearance and structure of DNA, altering how a gene can interact with important interpreting (transcribing) molecules in the cell’s nucleus.
“Genes carry the blueprints to make proteins in the cell. The DNA sequence of a gene is transcribed into RNA, which is then translated into the sequence of a protein. Every cell in the body has the same genetic information; what makes cells, tissues and organs different is that different sets of genes are turned on or expressed.
“Because they change how genes can interact with the cell’s transcribing machinery, epigenetic modifications, or ‘marks’, generally turn genes on or off, allowing or preventing the gene from being used to make a protein.
On the other hand, mutations and bigger changes in the DNA sequence (like insertions or deletions) change not only the sequence of the DNA and RNA but may affect the sequence of the protein as well. (Mutations in the sequence can prevent a gene from being recognized, amounting to its being turned off but only if the mutations affect specific regions of the DNA.)
“There are different kinds of epigenetic “marks,” chemical additions to the genetic sequence. The addition of methyl groups to the DNA backbone is used on some genes to distinguish the gene copy inherited from the father and that inherited from the mother. In this situation, known as “imprinting”, the marks both distinguish the gene copies and tell the cell which copy to use to make proteins.
“Imprinted genes don’t rely on traditional laws of Mendelian genetics, which describe the inheritance of traits as either dominant or recessive. In Mendelian genetics, both parental copies are equally likely to contribute to the outcome. The impact of an imprinted gene copy, however, depends only on which parent it was inherited from. For some imprinted genes, the cell only uses the copy from the mother to make proteins, and for others only that from the father.
“Imprinting in genetics is not new but it is gaining visibility as it is linked to more diseases and conditions that affect humans. Centuries ago, mule breeders in Iraq noted that crossing a male horse and a female donkey created a different animal than breeding a female horse and a male donkey.
In the modern scientific era, however, the initial evidence for parent-of-origin effects in genetics did not appear until the mid 1950s or so.
“Then, in the mid 1980s, scientists studying mice discovered that inheritance of genetic material from both a male and a female parent was required for normal development. The experiments also revealed that the resulting abnormalities changed depending on whether the inherited genetic material was all male in origin or all female.
“Around the same time, others discovered that the effects of some transgenes (genetic material transferred from another organism) in mice differed when they were passed from the male or female parent. The first naturally occurring example of an imprinted gene was the discovery of imprinting in the IGF-2 gene in mice in 1991, and currently about 50 imprinted genes have been identified in mice and human”.(14)
Gene expression is concerned not only with differentiation but also the way in which a cell behaves. Substrates can alter enzyme activity. The study of gene expression is now providing evidence that substrates can work by acting on DNA itself. Dr K. Yokuyama in Japan has studied the synthesis of a membrane lipid using simple systems. He identified the specific region in a yeast DNA which coded for an enzyme, choline kinase, which was known to respond to levels of substrates for making membrane lipids. To obtain a clean experiment he isolated this section of the yeast DNA and inserted it in to the genetic mechanism of a bacterial strain of E. coli which did not possess these enzymes.
This technique enabled him to examine the behaviour of the piece of yeast DNA free from the confusing effects of related systems in the yeast.
He then proved that the bacterium not only produced choline kinase but that the inserted gene made different amounts of enzyme depending on the amount and type of substrates which he fed to the bacterium. By deleting sections of the DNA code bit by bit he was able to identify a section of the code which responded to the substrates in the medium and switched on the synthesis of the enzyme. Here is probably the closest to proof that external substrates are acting on the genetic mechanism.
Dr Yokuyama also discovered that the substrates that stimulated the gene expression for choline kinase also stimulated the expression of a related enzyme, ethanolamine kinase. Both enzymes are used for membrane growth.
Such coincident expression offers a mechanism for the co-ordination of genetic expression.(15)
In Paris Dr M. Mangeney has shown that certain messenger RNA molecules which translate the DNA information for the cell to make proteins, are under the control of insulin and glucagons, two hormones responsive to the nature of food. Both these types of information describe how external influences can manipulate the amounts of products the cell can make.(16)
In 1988 John Cairns, Julie Overbaugh and Stephen Millar published ‘The Origin of Mutants’. They showed that the bacteria E. coli grown on a lactose medium responded in a manner which implied that a proportion of the bacteria have mechanisms for making just those mutations that adapted the cell to the presence of lactose which they could use as an energy source. In other words by plating the E. coli, which had previously no experience of lactose, on to a lactose medium bacterial mutants arose with the ability to use lactose in a manner which would not have been predicted had there been the odd random lactose utilising bacteria present before the plating. They say “The main purpose of our paper is to show how insecure is our belief in the spontaneity (randomness) of most mutations. It seems to be a doctrine that has never been properly put to the test”.(17) As a mechanism they suggest a form of reverse transcription leading to ‘a directed mutation’, which basically means information flowing back from the cell to the DNA. ‘If a cell discovered how to make that connection, it might be able to make some choice over which mutations to accept and which to reject’. The original studies on such models led people to believe that natural selection was at work. However, in these latest studies it seems as though it is the substrate which is driving the reprogramming of the genetic information.
This type of evidence on adaptive enzymes and directed mutation is only a short step from an understanding of how such manipulations could ultimately be expressed in animal form.
It is perfectly plausible that the change in average human height since 1900 could have been induced by just such a mechanism. Change in form could be simply brought about by the response of the DNA and enzymes to changing inputs.
Marcus Pembrey, Professor of Clinical Genetics at the Institute of Child Health in London, is a scientist who believes your genes are shaped in part by your ancestors’ life experiences and that biology stands on the brink of a shift in the understanding of inheritance. The discovery of epigenetics, hidden influences upon the genes, he suggests, could affect every aspect of our lives.
At the heart of this new field is a simple but contentious idea, that genes have a ‘memory’. That the lives of your grandparents, the air they breathed, the food they ate, even the things they saw can directly affect you decades later despite your never experiencing these things yourself. And that what you do in your lifetime could in turn affect your grandchildren.
The conventional view is that DNA carries all our heritable information and that nothing an individual does in their lifetime will biologically be passed to their children. To many scientists epigenetics amounts to a heresy, calling into question the accepted view of the DNA sequence, a cornerstone on which modern biology sits.
‘Epigenetics’ he explains ‘adds a whole new layer to genes beyond the DNA’. It proposes a control system of ‘switches’ that turn genes on or off and suggests that things people experience, like nutrition and stress, can control these switches and cause heritable effects in humans.(18) For those wishing to follow this exciting work further, the BBC did an excellent programme on Pembrey (et al.’s) work entitled ‘The Ghost in your Genes’. As the programme explained ‘This work is at the forefront of a paradigm shift in scientific thinking. It will change the way the causes of disease are viewed, as well as the importance of lifestyles and family relationships. What people do no longer just affects themselves, but can determine the health of their children and grandchildren in decades to come’. “We are,” as Marcus Pembrey says “all guardians of our genome.(19)
Speaking at the McCarrison Society conference at the Innkeepers Hall, London (January 2006), Professor Barry Keverne (Behavioural Neuroscience, King’s College, Cambridge) described the significance of genomic imprinting for brain development and behaviour.
Keverne explains how genetic imprinting “provides for outstanding coadaptation of mother and fetus, for maternal provision and fetal use of resources. “On the other hand” he continues “it is open to genetic transmission of clinical disorders, for instance Prada-Willi syndrome leading to obesity and Angelman’s syndrome with unusual behaviour.
“Genetic imprinting only evolved in mammals and the placenta is deeply involved. Imprinting explains the much greater variety of species from such a small percentage difference in genes and the small number of human genes that so surprised scientists of the Human Genome Project.
“There are certain genes in mammals that are only expressed if inherited from one parent rather than from the other. More often the paternal gene, or allele, is expressed which means that the maternal allele is silenced, usually by methylation; bonding of a CH3 group. “Genomic imprinting, distinct from epigenesis, occurs in germ-line cells with transgenerational effect. Epigenesis, in somatic cells, genetically affects the individual only, though if it causes a change of behaviour, better mothering say, that can affect the next generation culturally. “Imprinting is reversible and there is no change in the gene sequence, unlike mutation. Genomic imprinting acts primarily through key regulatory genes which in turn have a cascade effect through other genes.
“Possible effects vary widely, for example the mother’s food intake and weight gain; maternal fat and blood glucose; letdown of milk and post-natal pup growth. Other effects include her maternal behaviour, nest-building and placental hormones, placental blood flow and nutrient transfer, fetal growth and early weaning and puberty onset.
“In these ways the placenta enables the fetus to regulate its own destiny, mainly by genomic co-adaptation affecting hormonal action on receptors in the maternal hypothalamus. The two genomes, infant and maternal, are coadaptive for infant wellbeing and reproductive success. Offspring that have extracted “good” maternal nurturing will be genetically predisposed towards good mothering.
“Early fetal mortality helps selection for fitness. Through imprinting, a gene contributing to fitness is established in the population more quickly, especially when paternally expressed. Although imprinting affects hormonal activity and nutrient metabolism there is no evidence that hormones or nutrients affect genomic imprinting. Hormones and nutrients can, particularly in early life, epigenetically affect the individual’s future life for better or for worse and seriously contribute to obesity.”(20)
Finally we can take a look at how these epigenetic traits are being applied to medicine. In describing ‘Neo-Lamarckian medicine’ Professor R. Gorlick, (then Assistant Professor, Department of Biology and School of Mathematics & Statistics, Carleton University, Canada) explains that ‘the underlying assumption of Darwinian medicine is the treatment of disease based on evolution’.(21) He suggests that in Darwinian medicine traits are seen to be coded by genes which are often assumed to come about by sequences of DNA nucleotides.
A commentator suggests that ‘the quantitative genetic ramification of this perspective is that traits, including disease susceptibility, are either caused by genes or by the environment, with genotype-by-environment interactions usually considered statistical artefacts’.
Gorlic stresses examination of those ‘epigenetic signals’ which can be varied by environmental pressures and then passed down future generations. He points out that whilst often not examined closely, those ‘signals’ which induce environmentally modification do exist, and further, that they ‘provide a mechanism underlying such genotype-by-environment interactions’. He states emphatically that parents’ environments can affect their progeny by generationally varying epigenetic signals. Neo-Lamarckian medicine he explains is ‘the application of these evolutionary notions to diseases’ suggesting that these could have powerful public health implications; also on decisions concerning environmental policy.
He comments that if industrial pollutants negatively affect living organisms by ‘meiotically-heritably’ varying epigenetic stimuli, then remedying the contamination will not remedy the problem. He suggests that once pollutants have negatively affected an individual’s epigenetic signals, this damage will be generationally transmitted even if such progeny are not subjected to the pollutant. Subjection to environmental insults such as free radicals or other carcinogens can ‘vary patterns of methylation on regulatory genes’.
This he says ‘can cause cancer by up-regulating genes for cell division or by down-regulating tumour suppressor genes’. ‘Environmentally-alterable meiotically-heritable epigenetic signals could also underlie other diseases, such as diabetes, Prader-Willi syndrome and many complex diseases. ‘If environmentally-altered meiotically-heritable epigenetic effects are widespread – which is an important open empirical question – they have the potential to alter paradigmatic views of evolutionary medicine and the putative dichotomy of nature versus nurture. Neo-Lamarckian medicine would thereby shift emphasis from cure to prevention of diseases’.(21)
February the 17th 2007 saw the publishing of the Bristol ALSPAC study in the Lancet. Analyses of these results were extraordinary. They showed that those women ignoring the advisory committees of both the FDA and FSA by eating more fish than advised (the major available source of long chain w-3 DHA) had babies which scored highest in the four main categories examined (see below).
Speaking at the FAB Research and McCarrison workshop at London Metropolitan University (Spring 2007) Dr Joseph Hibbeln from the IAAA at the NIH, USA described how since 1991the Bristol team recruited over 14,000 pregnant women into their study. Details of health, education, socio economic status, past pregnancies and diet were scrupulously recorded.
Approximately 8000 children born to these pregnancies have been followed up and provide a wealth of information on health, school performance, behaviour etc. The details of the mother’s diet enabled Dr. Hibbeln to relate maternal diet to subsequent school performance at 8 years of age. Mothers who adhered to the advice from FDA and FSA to consume no more than two portions of fish (one oily) and those who consumed little or no fish had babies who scored lowest with problems scattered across the board. These included verbal IQ, fine motor skills, presocial and social development.(22) This remarkable research showed that the official advice would cause more of the harm, especially with regard to the characteristics of child brain development, that the advisories were intended to prevent.
The advisories were based on increasing fish intake leading to increased intakes of methyl mercury. Yet there was no attempt to balance the increase in methyl mercury with the benefit of fish consumption. In fact, the evidence of harm comes from the use of mercury as a fungicide for seeds. After a crop failure and famine in Iraq several years ago sacks of such seeds were flown into for planting. The people being hungry ate the mercury laden seeds. Therefore there is evidence of serious harm at grossly high levels, levels which could never be reached by eating fish. Moreover there is no dose response data.
There is some evidence of mild harm from people in the Faroes eating pilot whale; this animal has high levels of methyl mercury but little selenium. Selenium is intrinsically needed to protect against peroxidation through the selenium glutathione peroxidase and also protects against mercury toxicity.
A similar study in the Seychelles, where people eat a lot of fish, did not confirm such damage but then fish are very different from pilot whales which may contain several other confounders apart from selenium deficiency.
Yet the Japanese eat fish and sea food almost every day and often more than once a day and have some of the best health statistics in the world.
Moreover, if a woman is advised not to eat more than two portions of fish a week when pregnant, she will immediately suspect that there is something bad about fish and it could well put her off eating any fish. According to the World Health Organisation (WHO) the Japanese and Icelanders are the two nations with the best birthweights and longevities.
Remembering that “DHA stimulates the expression of over 107 genes involved in neural development, function and metabolism, a supply of preformed DHA would confer an advantage to the intellectual development of an evolving primate”.(24) It cannot just be a sad coincidence that the UK has one of the highest rates of low birthweight in Western Europe. It’s encouraging to know that with a collective will we can now do something about it.
Recent American research which supports this thesis. In ‘Human evolution, radically reappraised’ anthropologists John Hawks of the University of Wisconsin-Madison and Gregory Cochran of the University of Utah in Salt Lake City show how ‘Human evolution has been speeding up tremendously, so much, that the latest evolutionary changes seem to largely eclipse earlier ones that accompanied modern man’s “origin”.
The study, alongside other recent research on which it builds, amounts to a sweeping reappraisal of traditional views, which tended to assume that humans have reached an evolutionary endpoint”.23 “The findings suggest that not only is our evolution continuing: in a sense our very “origin” can be seen as ongoing.
A geneticist not involved in the study said “Hawks and Cochran also analyzed past genetic studies to estimate the rate of production of genes that undergo positive selection – that is, genes that spread because they are beneficial. “The rate of generation of positively selected genes has increased as much as a hundredfold during the past 40,000 years,” they wrote.
Hawks and Cochran said some of the most notable physical changes in humans have been ones affecting the size of the brain case. A “thing that should probably worry people is that brains have been getting smaller for 20,000 to 30,000 years,” said Cochran. But brain size and intelligence aren’t tightly linked, he added. Also, growth in more advanced brain areas might have made up for the shrinkage, Cochran said; he speculated that an almost breakneck evolution of higher foreheads in some peoples may reflect this.
A study in the Jan. 14 (2007) British Dental Journal found such a trend visible in England in just the past millennium, he noted, “a mere eyeblink in evolutionary time”. For full article see: http://www.worldscience. net/exclusives/070326_evolution.htm
So was Lamarck right? My suggestion is the same as we published a decade or so before completion of the human genome map. In “The Driving Force, Food in Evolution and the Future” in 1989 and later in 1995 in “Nutrition and Evolution”25, 26 when Professor Michael Crawford and I stated our belief that both were right: that natural selection and environment work hand in hand.
Furthermore current science is clearly showing us what Charles Darwin wrote in 1859, “that two great engines are driving evolution, natural selection and conditions of existence”. He saw them as one and that if anything ‘conditions’ came first. So now Darwin and Lamarck can converse with some agreement!
Its time to do something about this; teach young children to like fish, sea foods, seaweeds and beneficial algae like spirulina and chlorella. For the sake of future generations please [breed and] eat more aqua-foods! They are the main and richest source of brain specific nutrients. Water covers 70% of our planet’s surface and potentially represents our greatest future food source. We kill or foul our oceanic, riverine and lacustrine habitats at our peril.
I have no conflict of interest to declare.
1. Kuhn, T (1970). The Structure of Scientific Revolutions (2nd ed). Chicago, University of Chicago Press.
2. Lamarck, J-B. (1873). Philosophie Zoologique, ed Martin, Charles (2 vols), Paris, Savy.
3. Malthus, T.R. (1798). An Essay on the Principle of Population, as it Affects the Future Improvement of Society. London, printed for J.Johnson, in St Paul's Church-Yard.
4. Darwin, C. (1859). On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. 1st Edition, London. John Murray.
5. Darwin, C. (1872). On the Origin of by Means of Natural or The Preservation of Favoured in the for Life. 6th Edition, London. John Murray.
6. Weismann, A. (1894). The Effects of External Influences on Development. Romanes Lecture, London, Frowde.
7. Mendel read his paper “Experiments on Plant Hybridization”, at two meetings of the Natural History Society of Brünn in Moravia in 1865. Mendel's paper was published in 1866 in Proceedings of the Natural History Society of Brünn.
8. Bowler, P.J. (1983). Johns Hopkins University Press, Baltimore, Maryland USA.
9. Koestler, Arthur (1971). The Case of the Midwife Toad. Random House.
10. Kammerer, Paul (1924). The Inheritance of Acquired Characteristics. New York: Boni and Liveright Publishers.
11. See 18.
12. Goldsmidt, R. (1940). The Material Basis of Evolution, Yale University Press, New Haven.
13. Watson, J.D. , Crick, F.H.C. (1953). Molecular Structure of Nucleic Acids: A for Deoxyribose Nucleic Acid. Nature 171, 737–738 (25 April); doi:10.1038/171737a0 Medical Research Council Unit for the Study of the Molecular of Biological Systems, Cavendish Laboratory, Cambridge. April 2.
14. Downer, Dr Joanna Johns Hopkins Medical Institutes. mailto:email@example.com) full text see file:///C:/Documents%20and%20Settings/David%20Marsh/My%20Documents/EPI%20Backgrounder%20Epigenetics%20and%20Imprinted%20Genes.htm
15. Yokuyama, K. (1988). 29th International Conference on the Biochemistry of Lipids, Tokyo.
16. See Driving Force 25, 26.
17. Cairns, John , Overbaugh, Julie J. , and Milla, Stephen (1988). The Origin of Mutants. Nature, 3235, 142–145.
18. Pembrey, M. (2006). Epigenetics. Sex-specific, male-line transgenerational responses in humans. Eur J Hum Genet. 14 (2), 159–66.
19. “The Ghost in your Genes ' http://www.bbc.co.uk/sn/tvradio/programmes/horizon/ghostgenes.shtml
20. Professor Barry Keverne FRS, FMedSci - Behavioural Neuroscience, King's College, Cambridge. ebklO@cus.cam.ac.uk
21. Gorlick, R. Neo-Lamarckian medicine. Med Hypotheses. 2004; 62(2):299–303. PMID: 14962644 [PubMed - indexed for MEDLINE] http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Search&itool=pubmed_AbstractPlus&term=%22Gorelick+R%22%5BAuthor%5D School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA. firstname.lastname@example.org http://www.aecom.yu.edu/home/pediatrics/hematology_oncology.htm Associate Professor of Pediatrics and Molecular Pharmacology Chief, Section of Hematology/Oncology: Albert Einstein College of Medicine, Yeshiva University, USA.
22. Avon Longitudinal Study of Parents and Children study (ALSPAC). Dr Hibbeln MD is Chief of Outpatient Clinic, Lab of Membrane Biophysics and Biochemistry, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, United States Public Health Service Commander.
23. Hawks, J. , Cochrane, G. (2007). Human evolution, radically reappraised; World Science March 26, see web link http://www.world-science.net/exclusives/070326_evolution.htm
24. Kitajka, K. , Sinclair, A.J. , Weisinger, R.S. , Weisinger, H.S. , Mathai, M. , Jayasooriya, A.P. , Halver, J.E. , Puskas, L.G. (2004). Effects of dietary omega-3 polyunsaturated fatty acids on brain gene expression. Proc Natl Acad Sci USA, 101(30), 10931–6.
25. Crawford, M.A. , Marsh, D.E. (1989). The Driving Force, Heinemann, London.
26. Crawford, M.A. , Marsh, D.E. (1995). Nutrition and Evolution, Keats, USA.
Szeto, I.Y.Y. , Barton, S.C. , Keverne, E.B. , Surani, M.A. (2004). Analysis of imprinted murine Peg3 locus in transgenic mice. Mammalian Genome 15, 284–295.
Curley, J.P. , Barton, S.A. , Keverne, E.B. (2004). Coadaptation in mother and infant regulated by a paternally expressed imprinted gene. Proc. R. Soc. Lond. B 271, 1303–1309.
Keverne, E.B. (2004). Brain evolution, chemosensory processing, and behavior. Nutrition Reviews 62, S218–S223.
Curley, J.P. , Pinnock, B. , Dickson, L. , Thresher, R. , Miyoshi, N.M.A. , Keverne, E.B. (2005). Increased body fat in mice with a targeted mutation of the paternally expressed imprinted gene Peg3. FASEB J. 19, 1302–1304.
Bruce Lipton PhD . http://www.brucelipton.com/references.phpm
Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life Jablonka, E. and M.J. Lamb (2005). Bradford Books. Darwin 's Blind Spot: Evolution beyond natural selection. Ryan, F. (2002). New York, Houghton Mifflin.
The Evolution of Genetic Intelligence David S. Thaler Science 1994, 264, 224–225 (Discusses new papers which verify adaptive (Cairnsian) mutations, new gene control scheme compared to Darwinian scheme).
Evolution Evolving* Tim Beardsley Scientific American September 1997, pages 15-16 (Provides the first notice of Cairns' study to the “general public,” almost ten years after it was first published.)
Epigenetics: Genome, Meet Your Environment. Leslie Pray , The Scientist 2004, 18(13), 14 (Review of molecular mechanisms used in epigenetic control).
Mother nature meets mother nurture J.C. Crabbe and T.J. Phillips Nature Neuroscience 2003, 6, 440–442 (Intrauterine and postnatal care alter gene expression and behaviour in adulthood).
Nature, nurture and human disease. Chakravarti, A. , and Little, P. Nature 2003 421, 412–414 (How environment can cause disease through epigenetic mechanisms). http://www.hofmann.org/papers/Lipton_Human%20Devel.html
Hugh Dower, Evolutionary Philosopher. The Repercussions of Aquatic Ape Theory. http://www.hughdower.com/Ape.htm