Historically, Lamarck has been somewhat of an outcast in academia, and his posthumous association with the Bolsheviks has not done his image any favors. However, some recent research has suggested that maybe we should not have thrown out the baby with the bathwater. Evidence is mounting that there is a Lamarckian component to evolution, and that it may exert subtle but important effects on how we behave.
Darwin, contrary to popular, belief is not the father of evolution. That distinction belongs to Jean-Baptiste Lamarck (1744-1829). Lamarck, who died 30 years prior to the publishing of The Origin of Species, was the not first person to espouse the idea that species were not immutable (I believe that distinction belongs to Buffon--at least in "modern" times), but he was the first to try to outline a mechanism by which species changeover time. According to Darwin, “Lamarck was the first man whose conclusions on the subject excited much attention. This justly celebrated naturalist first published his views in 1801...he first did the eminent service of arousing attention to the probability of all changes in the organic, as well as in the inorganic world, being the result of law, and not of miraculous interposition[1].” Lamarck, in a stroke of immeasurable insight proclaimed that, “. . . time and favorable conditions are the two principal means which nature has employed in giving existence to all her productions. We know that for her time has no limit, and that consequently she always has it at her disposal (qtd. in [2]).” This is not only true, but revolutionary, given the academic climate of the day.
Where Lamarck went wrong—or so the story goes—is in the mechanism he proposed. This mechanism has come to be known as “inheritance of acquired characteristics”. In the famous example, Lamarck pointed to a giraffe, and hypothesized that over many generations the giraffe’s neck had grown longer due to ever more stretching to reach the highest branches by previous generations. Each giraffe made his neck a bit longer, and so her offspring’s necks will be a litter longer as well. He proposed a theory of use and disuse to explain how species evolve. Essentially if an organ is not used, it will shrink, and the progeny’s organ will be smaller as a result. The opposite applies for oft used organs.
When Darwinism took hold in the latter half of the 19th century, it all but eviscerated Lamarck, and, as happens in history from time to time, we more or less threw out the baby with the bathwater, saying simply that “Lamarck was wrong”, while ignoring all of the other brilliant things he had to contribute.
But there was one group who revered Lamarckism: the post-revolutionary Russian scientists. They, however, did not refer to their thinking as being Lamarckian, apparently due to his aristocratic background, which was a non-starter in Soviet Russia, especially in the early days after the Revolution. The inheritance of acquired characteristics was “rediscovered” in the 1920s by a Ukrainian agricultural scientist by the name Trofim Lysenko (I say scientist in the loosest possible meaning of the term; Lysenko was not formally trained as a scientist and most certainly did not follow the scientific method). Lysenkoism became official doctrine of the USSR, and disputing it was a criminal offence, leading to the sacking of university professors, and apparently even in some cases to exile in Siberia. But why did the Soviets take to this Neo-Lamarckism so? I’m not certain; I don’t know that anyone is, but I have a guess.
Let’s back up a bit, to the writings of a French philosopher, Claude Helvétius, who wrote in the decades before the French Revolution, which the socialists in Russia looked to and intently studied for guidance in handling their own struggle. Citing Locke’s Essay on Human Understanding, in which Locke posited that human ideas derive from and are reflexive to experiences and sensory inputs alone, Helvétius believed that the natural extension of this theory was the law and morality are inextricably linked. If, he reasoned, humans were shaped solely by experience, then it is only natural that controlling a man’s experiences will no doubt control his actions. One’s entire character can be shaped by good governance. He wrote, “It is…only by good laws that we can form virtuous men.” For Helvétius, reason causes virtue. According to the historian Richard Pipes:
So, rationality is the path to happiness, and socialism is rational. Therefore, socialism is happiness incarnate.
What does this have to do with Lysenko? (Or Lamarck for that matter?) The answer can be found in the application of the principles behind the inheritance of acquired characteristics. Lysenko claimed to have developed a breed of wheat—and later a breed of peas, among other increasingly fantastical claims—that he altered in such a way that they had a different planting season than when wheat was typically planted (a process he called “vernalization”). It would now be possible to turn deserts into pasture, times of famine into feast. However, even more remarkably, Lysenko claimed that successive generations of his seeds did not need to be vernalized, that the offspring of his vernalized wheat was itself already vernalized [4]. He had altered the plant’s genetics! It stands to reason (or rather it stood to reason for the Communist elite) that if the genes of plants could be manipulated by careful processes, why not humans? Could they develop a purely rational, virtuous man by tinkering with his biology? And could this be done through laws, as Helvétius predicted? To the Bolsheviks, Lysenkoism was a true proof of their theory of society.
Unfortunately for the Bolsheviks, much, if not all, of Lysenko’s work turned out to be fraudulent. (Or apparently, not even fraudulent, given that he would often just publish his ideological musings and speculations without much in the way of data.) So it seemed that Darwinism and Mendelian genetics have stood the test of scientific rigor, prediction, experimentation, and repeatability, while Lamarckian evolution has turned out to be not much more than a dream, a clever thought from a revolutionary thinker that has not been backed up by prediction and testing. And to add insult to injury, the West came to see Lamarckism as synonymous with Lysenkoism, and ultimately Bolshevism. In fact, “…the unfortunate saga of Lysenko made the very idea of a Lamarckian mechanism actually operating during evolution repulsive and unacceptable to most biologists [5].” Until now, that is.
Fast forward from the 1920s to 2009 (ok, ok, actually a decade or so earlier, but I’m not so interested in subtle discussions on gene transfer in unicellular organisms). In that year, two separate studies in rodents showed that newly acquired traits can in fact be passed on to progeny. In one study, researchers at University of Alabama-Birmingham wanted to test the effects of simulated early life child abuse on neural development [6]. They exposed infant rat pups to a stressed out mothers who consistently showed abusive type behaviors. Not surprisingly, they observed changes in the developing brains of the rat pups. Specifically, they found that an important gene that controls brain growth, brain derived neurotrophic factor (BDNF), was methylated in the abused pups. DNA methylation inhibits a gene’s expression, and it is an important process in epigenetics, the regulation of how and when genes are expressed. However, they made a remarkable observation: The DNA encoding the BDNF gene was methylated in the offspring of the female rats that had been abused as infants! Thus, they showed that environmental changes in one organism can produce the same effect, a real, physical, measurable effect in the organism’s children.
In the other study, a group at Tufts University showed that exposing young rats to extra enrichment, such as learning tasks and novel objects, not only helped their cognitive abilities, but also potentiated their offspring’s capacity for learning and memory, as well [7]. This effect persisted even in rats that were genetically engineered to have molecular defects that cause cognitive deficits. The team concluded that, “If a similar phenomenon occurs in humans, the effectiveness of one's memory during adolescence, particularly in those with defective cell signaling mechanisms that control memory, can be influenced by environmental stimulation experienced by one's mother during her youth.” In other words, if a girl studies hard and challenges herself as a youth, she may one day unwittingly help her children to be better students.
Other studies have shown that not just epigenetics, but small RNAs, known as microRNA (or miRNA), whose function is to block the translation of mRNA into protein, can have effects on offspring, as well. Particularly, a study published last year from University of Wyoming suggests that obesity in pregnant mothers can affect the miRNA profile in her babies, perhaps making them more susceptible to becoming obese themselves [8]. This research, while fascinating, is also frightening, as it suggests that out obesity epidemic may be getting worse by changing our gene expression profile, leading to a death spiral of fat.
So these converging lines of research show that both positive and negative environmental influences on us can have profound influences on our children through no fault of their own, perhaps creating a positive feedback loop that could have advantageous or deleterious effects. The extent to which this phenomenon contributes to human behavior is not yet known, but either way this is remarkable. And, in my opinion it should restore a long forgotten public debate about the ideas of Helvétius. Do we have a moral responsibility to take care of ourselves in order to preserve a better world for our children? Or, more poignantly, does the government have the right to legislate us into being better citizens? After all, perhaps subsequent to several generations of forcing young children to undergo enhanced cognitive stimulation, we could have a more enlightened society. It is a very tough ethical question, but I think one that deserves consideration in light of what biology has brought to light in recent years. One thing is certain; Lamarck lay dormant for many years but never died.
[1] Darwin C. The Origin of Species. 1861, Introduction to 3rd edition
[2] Alpheus S. Lamarck, the Founder of Evolution. 1901, New York: Longmans, Green, and Co.
[3] Pipes R. The Russian Revolution. 1990, New York: Knopf.
[4] Joravsky D.The Lysenko Affair. 1986, Chicago: University of Chicago Press.
[5] Koonin E, Wolf Y. Is evolution Darwinian or/and Lamarckian? Biol Direct. 2009.
[6] Roth TL, Lubin FD, et al. Lasting epigenetic influence of early-life adversity on the BDNF gene. Biol Psychiatry. 2009.
[7] Arai JA, Li S, et al.Transgenerational rescue of a genetic defect in long-term potentiation and memory formation by juvenile enrichment. J Neurosci. 2009.
[8] Yan X, Huang Y, et al. Maternal obesity downregulates microRNA let-7g expression, a possible mechanism for enhanced adipogenesis during ovine fetal skeletal muscle development. Int J Obes. 2012.