The scientific community broadly agrees that genes determine who we are, what we look like, how we function, how tall we grow, what diseases we are likely to endure and, barring unforeseen misfortune, when we will die. These genes are with us from the moment of conception. And when we in turn conceive a child, they are passed on from both mother and father unaltered by the experiences of a lifetime. It is irrelevant that during our own life we may have developed new abilities or powerful immunities to disease. Genes learn nothing from a life lived despite the potential for evolutionary benefit.
Or do they?
In 1809, Jean-Baptiste de Lamarck proposed that characteristics acquired during a lifetime could be passed on to the next generation. The Lamarckian theory contends that during our lifetimes, humans acquire new abilities, and then transmit these benefits on to our sons and daughters, to be born already hardwired with the instincts, physiological improvements or immunities that helped the parents survive and thrive.
Fifty years later however, when Charles Darwin sowed the seeds of change with the publication of his own theory of evolution in On the Origin of Species, the scene was set for scientific devotion to the one-way hereditary process. After another fifty years, the discovery of genes cemented the dogmatic era of Neo-Darwinism and Lamarck’s original theory of evolution was under siege.
Darwin got his theory of evolution pretty right. His natural selection was pivotal in the history of biological evolution. But the missing part was the deal-breaker. The missing link in Darwin’s theory of evolution was the mechanism of inheritance. Additionally he never provided an explanation for the generation of new species, let alone that gigantic leap of evolutionary progress that sees an aquatic animal breathing with gills emerge from the water and start using lungs on dry land. And his great book, On the Origin of Species, never did explain the origin of species.
Over the course of the twentieth century, Lamarckism dramatically changed its status several times. It went from a perfectly acceptable scientific doctrine during the 1920s to become scientifically unacceptable by the 1950s. Throughout the second half of the twentieth century, antipathy to Lamarckism and a fear of sounding in any way Lamarckian continued thanks to the scientists who energetically tried to expunge from biology any trace of what they considered Lamarckian reasoning.
Jean-Baptiste de Lamarck would have wondered how his perfectly plausible and comprehensive theory of evolution had attracted those dwelling on the margins of science. What was there about this lucid piece of science that had so muddied the evolution of evolutionary theory?
Lamarck and Darwin changed our view of the world around us—from a place that was considered static to a universe filled with change. We now know that the continents beneath our feet are moving, that the universe itself is expanding, that life is changing, that we’re evolving, that we’re descended from ancestors with apes as cousins. For all this we are grateful to them both for making evolution a scientific fact. Today evolution remains an absolute plank of science, indeed pivotal to it. Its truths cannot be undone.
However, the origins of the theory of evolution and the form or shape of those origins are not quite so immutable. Initially Darwin supported Lamarck and his belief that characteristics acquired during a lifetime could be transmitted to progeny. Yet latter-day Neo-Darwinists selectively interpret the writings of Charles Darwin to exclude any positive reference to Lamarck. They declare Lamarck an irrelevant and vestigial organ of history, a curious historical caricature who, while well-intentioned, got it comprehensively wrong. As we will see, it was they, not Lamarck, who got it wrong.
Nonetheless, the twentieth-century scientific establishment embraced Neo-Darwinism, and in doing so precluded the transfer of acquired characteristics into the gene pool. For Neo-Darwinists, hereditary information comes only from DNA in our sex cells. Our body cells, the building blocks of our entire being, have no say in the matter. It’s a one-way street with a brick wall at one end. This imaginary mechanism is known as the Weismann Barrier, named after the nineteenth-century biologist August Weismann, who proposed that DNA in those very few sex cells—sperm and eggs—remains unchanged as a repository of the instructions that determine the next generation.
The Neo-Darwinian approach has the world evolving in a way that relies on chance genetic mutations or changes, and natural selection: a gene changes randomly and natural selection ensures that only the beneficial changes survive. This approach precludes genes being influenced or changed by events going on in the body, with the benefit of experience being lost at every final closing of the eyes. Neo-Darwinists believe that our lives have no influence on evolution and are the result of a random past rather than the cause of a better future.
For a century, Neo-Darwinism ruled and Lamarck struggled for recognition. That is, until a young Australian scientist named Ted Steele, in a moment that changed his life, discovered Jean-Baptiste de Lamarck. And Steele’s work helped alter the course of scientific history.
Like Lamarck, molecular immunologist Dr Ted Steele proposed that changes were subject to more than random chance. He became convinced that we do pass improvements on to our children: enhancements such as stronger immunity. But, in the tradition of Lamarckian scientists throughout the nineteenth and twentieth centuries, while Steele believed passionately in the logic of Lamarckian evolution, for many years he had no proof, no hard scientific evidence.
Then in 1978, Steele produced evidence that acquired immunity can indeed alter genes for transmission to future generations. In discovering the evolutionary mechanism Steele crossed the Weismann Barrier and in doing so traversed the scientific fault-line.
Steele’s scientific experimentation provided the elusive evidence that messages from the soma or body cells could indeed be passed back, across the Weismann Barrier, and written into the DNA. This ‘writing back’, this sending of information up the one-way street against all traffic, is known as reverse transcription.
Ted Steele believed he had changed the basis for all evolutionary thought. He had proved Lamarck correct. However the struggle to convince the scientific establishment of his breakthrough cost him his promising career and his reputation. His evidence was discredited. He was attacked, vilified, sacked and derided. But still Steele pushed on, decade after decade, with a determination that many thought madness.
Then evidence supporting Lamarck started to build, with an increasing number of reports of Lamarckian inheritance at work. An early example receiving fresh attention is the case of the peppered moth, found in northern England. The typical moth in England prior to the industrial revolution was the dominant light-coloured form. Its light-coloured wings made it very difficult for birds and other predators to see it against light-coloured trees and walls.
Then, around the middle of the nineteenth century, a new dark form of the moth began to appear, and by the end of the century almost all the peppered moths in Manchester were of the dark variety. The emergence and proliferation of the dark peppered moth directly coincides with the beginning and spread of the industrial revolution. The coal that was burned as industry spread throughout the north of England blanketed the countryside with black soot and the dark moth was as hard to see against the newly blackened environment as the light moth was against the earlier, cleaner landscape. Additionally, several naturalists reported that the light moth was more prevalent in the countryside, while the dark moth prevailed in the sooty towns and cities.
Following the closure of coal mines and many industrial centres by Margaret Thatcher, and the more recent introduction of clean air laws in Britain, the landscape has changed back, even in industrial areas, and the sootiness that prevailed during the nineteenth century has disappeared from the cities of England. Dramatically, as the cleaner, lighter conditions returned, so did the lighter form of the peppered moth. Some biologists even suggest that the dark moths will soon be extinct.
For evolutionary biologists, the question is why should the dark moth have appeared so suddenly, come to dominate the population in industrial areas, and then have declined just as sharply when pollution levels dropped? Under the Meta-Lamarckian conditions, the event of radical environmental change reverse-transcribed new information back into the genome creating a changed progeny that in turn survived through natural selection. Regardless of the research methodologies used to measure the moth populations, and some are controversial, the peppered moth and its remarkable change stands as a poetic allegory to the vast possibility for reverse transcription and Lamarckian inheritance.
The peppered moth example also highlights the dramatic difference in the pace of change between Lamarckian and Darwinian evolution. Darwin and the Neo-Darwinists proclaimed that evolutionary change is slow, gradually occurring over thousands of generations and hundreds, even thousands, of years. In the case of the peppered moth, exhibiting Lamarckian speed, light moths reacted to the dirty conditions and a gene causing dark colouration was switched on simultaneously across the moth population. Those many moths were then able to breed—dark gene mother with dark gene father and their progeny emerged with dark wings.
Under the Darwinian model, totally random gene mutations for dark colour would have occurred throughout the history of the peppered moth until one day one gene in one chromosome in one moth produced a dark moth baby at exactly the right evolutionary moment—as the environment turned dark—and natural selection favoured the baby which then bred with a light mate producing a few dark offspring, and so on. A gradual process. A slow progression of evolution over decades. But the change did not happen over decades, it was much faster.
The real issue is whether a modern, well-supported Lamarckian theory can be devised, consistent with well-documented parts of modern molecular genetics, and be able to be articulated with a surviving core of Darwinian natural selection: a kind of Meta-Lamarckism that combines the best of both Darwin and Lamarck.
With the dawn of the twenty-first century, Lamarck’s widely discredited work began serious ascendancy. Steele’s indefatigable efforts over many decades gained purchase when other scientists around the globe started finding evidence that was Lamarckian in nature. In 2006, riding a wave of new evidence coming from across the globe, respected Italian geneticist Dr Corrado Spadafora and San Francisco-based molecular biologist Dr Patrick Fogarty separately and unequivocally produced evidence that the Weismann Barrier was an illusion. They delivered scientific proof that characteristics acquired during a lifetime can be passed on to sons and daughters by communicating new information from body cells to sex cells.
In March 2007, New Scientist magazine published a report titled, ‘A taste for milk shows evolution in action’. The magazine reported the results of a study by Mark Thomas of University College London who found that while most mammals grow out of drinking milk when they are weaned, Northern European humans don’t; they can digest lactose throughout their lives. The gene that allows them to digest milk appears to have been turned on in humans around the same time that farming started in Europe. The ability to digest milk would have given a massive survival advantage to people living a few thousand years ago. Milk from cows is uncontaminated by parasites, making it safer to drink than stream water. It is also available year-round, unlike most crops, and provides both calcium and some vitamin D, which may be in short supply during the sunlight-starved winters of northern Europe. Today more than 90 per cent of Europeans can digest milk, but Mark Thomas found evidence that this capability only developed during the past 7000 years. In most mammals, the enzyme lactase enables them to absorb lactose and is therefore essential in the digestion of milk. The gene gets switched off during adolescence. But not in adults whose ancestors came from long-term dairy farming areas like northern Europe.
To determine when northern Europeans acquired the version of the lactase gene that remains active in adult life, Thomas and his research team analysed the DNA from bone samples from eight Neolithic Europeans. Surprisingly, none of them had the ability to deal with lactose that modern-day Europeans demonstrate. Thomas concluded that the gene mutation for lactose tolerance arose in Europe within the past 7000 years and that natural selection quickly ensured its spread.
Mark Thomas claims that ‘the mutation for lactose tolerance arose spontaneously’, that a Darwinian genetic mutation occurred entirely at random providing an evolutionary survival advantage to Europeans. But is it not more probable that Neolithic humans in Europe, having domesticated cows and commenced farming, found milk a nutritious source of safe hydration and vitamins, and in doing so triggered a reverse transcription back into their DNA causing a gene mutation that ensured they could not only absorb the water and vitamins in milk but also the nutritious sugar known as lactose? Is it not more likely that lactose more frequently in their stomachs triggered the genetic change rather than an entirely random and coincidental genetic mutation? The lucky dip theory is sounding a little foolish given the evidence reported by Thomas and his team. And yet the Neo-Darwinists continue to refuse to acknowledge Ted Steele’s proposition that environmental changes can be passed back into the germline as an acquired characteristic; and Lamarck’s theory that characteristics acquired during a lifetime can be passed on to following generations.
Thomas does not think that this is a case of Lamarckian evolution. He believes the relevant genetic mutation has occurred many times throughout human evolution. His point is that, in the absence of dairying, there was no selective pressure to favour the new genetic variation so it would die out as quickly as it arose. It was only with the advent of dairying that the selective benefits of a lactase persistence gene would drive it to high frequency. Indeed, to him it seems likely that lactase persistence causing mutations have occurred a number of times, independently, in the last 10,000 years.
This Neo-Darwinian position—that it would have been a random mutation with natural selection favouring those with the new gene, ensuring its spread throughout subsequent generations—bemused Ted Steele when he learned of the research. Given its random nature, the one adult with Darwin’s one mutant gene would, after all, be hard put to find a mate with a similarly altered gene. No matter that the gene was absent for the entire history of the human species until the very moment that coincides with the beginning of farming and the domestication of cattle in Europe. The statistical improbability of such a coincidence being nothing more than random chance is, he thought, unimaginable.
Steele’s Lamarckism or Darwinism? Perhaps a combination of both: gene activation by reverse transcription and natural selection. This environmental change from hunter gathering to stationary farming was a major change in human behaviour, the kind of critical event that triggers a Meta-Lamarckian process.
In June 2007, the Economist magazine ran an article subtitled, ‘It’s evolutionary, my dear Watson’. It read:
What is being proposed is the inheritance of characteristics acquired during an individual’s lifetime, rather than as the result of chance mutations. This was first suggested by Jean-Baptiste de Lamarck, before Charles Darwin’s idea of natural selection swept the board. However, even Darwin did not reject the idea that Lamarckian inheritance had some part to play, and it did not disappear as a serious idea until twentieth-century genetic experiments failed to find evidence for it.
The article discusses the ‘re-admission of Lamarck’s ideas’ following a discovery that small RNAs are active in cells’ nuclei as well as in their outer reaches. Scientist Greg Hannon of the Cold Spring Harbor Laboratory in New York State believes that some of these RNA molecules are helping to direct subtle chemical modifications to DNA. They change the composition of the genome in a way similar to Darwinian mutation of the DNA itself (it is such mutations that are the raw material of natural selection). He contends that ‘they sometimes stimulate actual chemical changes in the DNA—in other words, real mutations.’
Of significance in this new milieu is that RNA, that original building block of life, is shaping up to be the dominant force in biological evolution.
Some scientists working on the origin of life present RNA as the first step in the evolution of cellular life. RNA, they argue, was not only at the beginning of life on Earth, it was the first step that life took with every living being on the face of the globe traceable back to that molecule. RNA was, however, unknown until the second half of the twentieth century. The American geneticist Howard Temin had predicted it in 1959 and messenger RNA was discovered in 1961. When DNA was identified as containing the blueprint of all bodily features and functions however, RNA was relegated to handmaiden status. It was viewed as the messenger that took instructions from the DNA and sent them out to the cells.
Scientific focus is now shifting from DNA as the supposedly immutable architect of life’s blueprints, to RNA acting as a courier delivering myriad messages from everyday experiences back to an ever-changing genome in the DNA. RNA is constantly evaluating environmental conditions and not only carrying that information back to the DNA, but also making its own decisions about what cells were produced and the form organisms would take.
Epigenetics—literally ‘above genetics’—has emerged as the new biology as Neo-Darwinian dogma falls from grace. Darwin’s natural selection is still considered to be the real thing, but the Neo-Darwinian obsession with random gene mutation as the determinant of evolutionary direction is increasingly seen for the fallacy it always was. It is as unreal as the Weismann Barrier. And today the world stands on the edge of a new scientific era.
Modern scientists, those biologists like Greg Hannon at the vanguard of the Lamarckian resurgence, are producing evidence for Meta-Lamarckism. Hannon identified something that Steele had at the heart of his theory—that the RNA operating system is the real player in the evolutionary process.
Under Steele’s theory involving reverse transcription, RNA is no longer the handmaiden. Meta-Lamarckism has RNA collecting changes from the soma and not only taking them back to the germline but also translating them into DNA language—into Mandarin so that an English telegram can be read in China.
Greg Hannon and his team identified the potential for acquired characteristics being passed on to the next generation. They don’t commit to Lamarckism but leave the door open. This is a paradigm shift for contemporary scientists.
But it is the whole new world of RNA that is exciting Ted Steele and the legacy of Jean-Baptiste de Lamarck. Some scientists even suggest that RNA goes beyond the job description that even the most adventurous biologists and geneticists have written for it. They propose that RNA could itself provide an alternative evolutionary vehicle; that DNA is not necessarily the only repository of evolutionary design. RNA may, they say, transport genetic information from one generation to the next independently of DNA. The Economist article suggests this may occur by the RNA hitching a lift in the sex cells.
Great advances continue. Enrico Coen and his colleagues at the UK’s John Innes Centre studied the difference between two similar but different plants, the common toadflax. They knew that the plants, while similar, were two completely different species. When they looked for differences in the genetic code of the two species however, they found none. The two species were genetically identical. Instead of their difference in petal shape being caused by a mutant gene, Coen found that the gene in question had been marked by a chemical tag; an instruction that the gene was not to be read.
Molecular biologists now know that even cloned animals with carbon copies of each other’s DNA can look dramatically different. That’s because of the way those genes are ‘expressed’. For example, if they’re Friesian cows, the pattern of their spots or the shape of their ears may be different. Human identical twins also have the same genes but because those genes are expressed differently in each person, they have different freckle and fingerprint patterns.
Forces outside DNA are at work determining which and why different genes are turned on and off. Environmental influences? Evolution is no longer just the selection and survival of genes within a species, but also how they are controlled and expressed. It can now safely be concluded that evolution is not an arbitrary, accidental process. Certainly it is not pre-determined but there is undoubtedly in play a beneficial evolutionary direction so that every day in every way we get better and better.
Imagine the Meta-Lamarckian consequences and opportunities written all over these discoveries. Steele identified RNA as the critical transcription vehicle because unlike DNA, it was the medium that was out there in contact with what was going on in the body. It was the obedient servant that knew the secret language, the secret handshake. What a breakthrough it was to discover from Lamarck via Steele that RNA could take vital changes back to the DNA for generational improvements. But imagine what it means if the RNA is capable of carrying its own information through generations. The Weismann Barrier, so beloved of the Neo-Darwinists is a joke.
In January 2008 an article in the prestigious journal Nature, titled ‘RNA-mediated epigenetic programming of a genome-rearrangement pathway’, revealed that a group of scientists at Princeton led by Laura Landweber had uncovered a new biological mechanism that could provide a clearer window into a cell’s inner workings. Online coverage of the article by Princeton University revealed, ‘What’s more, this mechanism could represent an “epigenetic” pathway—a route that bypasses an organism’s normal DNA genetic program—for so-called Lamarckian evolution, enabling an organism to pass on to its offspring characteristics acquired during its lifetime to improve their chances for survival.’
Is it not paradoxical that Lamarck’s mechanism for the process of evolution was supposedly disproved by the discovery of the role of DNA in genetic inheritance? DNA was the culprit, but RNA turned out to be the saviour. Jean-Baptiste de Lamarck and Charles Darwin are continuing to influence our understanding of evolution in ways that are unimaginable. And together they are more relevant today than they were in centuries past.
Lamarck’s evolution has been a journey of tribulation and triumph. The scientific establishment that for so long kept him out, that religious order known as Neo-Darwinism, is today less relevant than Charles Darwin reincarnated with Lamarck.
In a radio interview in 2007, the respected author and former editor of New Scientist magazine, Nigel Calder was asked for an example of a current orthodoxy he considered errant and that will be exposed as such. Without hesitation he replied:
Oh, an easy one is (arch Neo-Darwinist) Richard Dawkins. His account of evolution is hopelessly out of date. There are all kinds of things that happen to genes that just don’t figure in his way of thinking: all kinds of ways in which accelerated evolution can occur involving several genes at one time and yet the idea of the single mutation being tested by natural selection, which has been the dogma for what, seventy or eighty years, I mean it’s dead, defunct. But the people who are discovering the other things just don’t get reported very widely even though they are distinguished scientists themselves. I mean that to me is an example of where a top expert is wrong.
The world of evolutionary biology is a changed place. The evidence for Lamarck’s revolutionary theories continues to grow and, on an almost daily basis, the scientific establishment has to confront new truths. After two centuries, the truth of Lamarck has been established. This in no way diminishes Charles Darwin; they are partners in a new truth. Let us recall Dawkins’ words, ‘If something is true, no amount of wishing can make it untrue.’
So, the journey of Jean-Baptiste de Lamarck and Charles Darwin ends with a new beginning. Let the evolution begin.
1. The beginning of this essay draws upon the very lucid Steve Jones, professor of genetics at Galton laboratory of University College London.
2. Ernst Mayr’s What Evolution Is (Basic Books, New York, 2001) provides good insights into every aspect of evolution
3. The description of early dairy farming in northern Europe is informed by Tim Ingold’s Companion Encyclopedia of Anthropology (Routledge, New York, 1994).
4. The discussion on new research by Mark Thomas is informed by Roxanne Khamsi’s article ‘A taste for milk shows evolution in action’ (New Scientist, Issue 2593, 3 March 2007).
5. Comments about the effect of the lactose gene being purely Darwinian come from an email exchange between the author and Mark Thomas; the author is grateful for the assistance.
6. The discussion on RNA discoveries is informed by the article ‘Really new advances – RNA’ (Economist, Vol. 383, Iss. 8533, 16 June 2007).
7. The example of Enrico Coen and the toadflax plant is heavily informed by Nigel Calder’s Magic Universe: A grand tour of modern science (Oxford University Press, Oxford, 2003).
8. The final quote from Nigel Calder on Richard Dawkins ‘getting it wrong’ comes from Nigel Calder ‘In Conversation with Robyn Williams’ (ABC Radio National, 16 August 2007).