Lamarck’s Revenge
When I was young undergraduate in Biology 1001 my lecturer told we, the youthful bright-eyed audience, about the ludicrous, discredited evolutionary theory of Jean-Baptiste Lamarck. Lamarck, we were informed, laughably believed that animals acquired their defining physical characteristics due to the use of that characteristic by their parents.
The memorable example, revealed to several hundred of us in the vast lecture theatre, was the giraffe. Lamarckian evolution would postulate that mamma giraffe would strain her neck during her lifetime to reach high leaves. Later, upon producing offspring, bubba giraffe would be born with a slightly longer neck than expected. Bats’ wings. Tigers’ claws. Walrus’ tusks. All the wonder of the animal kingdom the result of parental stress and striving.
The lecturer stressed just how thick this theory was and then introduced us to Charles Darwin, who swept away the Lamarckian darkness 50 years after the death of the befuddled Frenchman. And we were invited to pelt rotten fruit at the enormous projected image of Jean-Baptiste, while Charles’ image was to be showered with garlands of flowers.
But now Lamarck seems to be having the last laugh.
Epigenetics
When I was quite a bit older, I attended postgraduate education in psychology. I was told about the Dutch Hunger Winter, a famine during Late World War II. The babies that were in gestation during this period went on to have higher rates of mental illnesses (and physical illnesses as well). But interestingly, children of women who were in gestation also had higher levels of mental illnesses. Illnesses thought to have a substantial genetic competent like schizophrenia.
We often think of genes as an “instruction manual” for making a certain living thing. We think usually think of this in terms of nature vs nurture. A cactus will always be a cactus, a frog will always be a frog. We can nurture a cactus or a frog to be slightly bigger or healthier. But no matter how you nurture a cactus, it will never become a frog. It won’t change its nature; our genetic instruction manual is written in permanent ink and won’t allow it. We’ve traditionally thought of nature/genetics as unbending to the forces of nurture.
We are now finding that the process of unfolding a living organism is actually more complex. An emerging finding from the last 20 years is that lifestyle factors of the parents of organisms can influence, in predictable ways, the characteristics of the offspring. This process is known as epigenetics.
At every stage of the developmental process, the emerging lifeform interacts with the environment (in mammals, like us, the early developmental environment is the uterus). During development, certain genetic “switches” are turned on or off, depending on the hormones and other chemicals present in utero. These switches may have a profound impact on observable characteristics (the phenotype) of the lifeform.
As the Dutch famine example indicates, lifetime stress can pass through generations. Other research has indicated that the American Civil War left a negative epigenetic impact. Likewise, the Holocaust.
Antifragility across Generations
So, how does antifragility fit into all this?
The famous epigenetic studies on human psychology centre on the deleterious effects of parental stress upon the offspring. War, famine, concentration camps. These truly are toxic levels of stress; these experiences have harmful effects on the health of the people who live through them. It seems normal that they would have harmful effect on future generations as well.
But what about moderate amounts of stress? Would moderately stressful experiences lead to a moderately negative impact on future generations?
A recent study, led by Dr Jeff Gidday published in the Journal of Investigative Ophthalmology & Visual Sciences shines a little light on the situation. Dr Jeff and friends exposed a bunch of mice to intermittent mild hypoxia – low oxygen levels the like of which might be caused be living at high altitudes or by exercising vigorously – prior to mating.
The offspring of these mice had retinas that were more resilient to injuries than those with parents not exposed to hypoxic conditions. Not all stress is bad for you one of the lead researchers said.
This is the early days of this type of research. This study is one of the first of its kind. It is not studying humans. Nevertheless, it is interesting to speculate whether a moderate amount of stress might fortify the next generation of young people.
So, there you have it. Jean-Baptiste Lamarck, not such an idiot after all! And toxic stress – bad for your children, and perhaps your children’s children down to the fourth generation (to paraphrase the bible). And bit of mild stress – well that makes you better, antifragile – and maybe helps your unborn kids too.