The legion purveyors of flapdoodle love a real but tricksy scientific concept that they can bolt their pernicious quackery on to. “Quantum” is surely the biggest offender, offering up some mystical scienceyness, none more so than in “quantum healing” – an unfathomable extension of reiki, which, let’s face it, is already graphene-thin flimflam. The annexing of this word from fundamental physics ranges from washing-powder branding to the theory of mind. “Quantum consciousness” is an idea that has generated some serious discussion over the years, but for me slots squarely into the category of “using one thing we don’t understand to explain another”.

Lots of real scientific terms – such as “neuro” or “nano” – get borrowed for a spot of buzzword scienceyness. Epigenetics is a real and important part of biology, but due to predictable quackery, it is threatening to become the new quantum.

All of your cells contain all of your 22,000 genes, but not all of them need to be active all the time. They need to be turned on or off, in the right tissue, at the right moment, and so we have incredible networks of control systems in our genomes – circuits, programmes, hierarchies. Epigenetics literally means “in addition to genetics” and is one such system – modifications to DNA without altering the gene sequence itself. Think of DNA as an orchestral score, the notes on the page unchanging. But the annotations on the manuscript will dictate how the music sounds, with crescendo and lento and adagio. The conductor and orchestra play their annotated manuscript, and each performance is unique, even when the original scores are identical.

Many individual genes are modulated, or tagged, like this too, and many corresponding traits are dependent on this system. We’ve known about this for decades. Rat mothers lick their pups, and those that are licked less have measurably higher stress levels, which correlates with less epigenetic tagging on genes associated with stress. What’s more, it’s reversible. So, the environment influences genetics.

In rural Sweden, life expectancy was significantly raised in men whose grandfathers had endured a failed crop season

In mammals, these types of modifications tend to get reset each generation, but here’s where it gets interesting, and irksome. Some limited, rare epigenetic tags can be passed down from parent to child. We’ve seen a handful of these in mice, even fewer in humans. One frequently cited study concerns the population of the rural Swedish district of Överkalix, which over the past century or so has been subject to highly variable harvests. Life expectancy was significantly raised in men whose grandfathers had endured a failed crop season just before puberty: they had acquired something due to starvation, and passed it on. A similar result from Bristol scientists using a huge data set – the Avon Longitudinal Study of Parents and Children, the gold standard of transgenerational research – showed that men who smoked before puberty sired fatter sons than those who smoked after. Again, something was being acquired and passed on.

Facebook Twitter Pinterest We have observed the effects of epigenetics in rodents for many decades. Photograph: Redmond Durrell/Alamy

In rodents, where the experiments can be controlled not merely observed, studies have shown learned behaviours such as fear or stress are passed on to their children, and even grandchildren, by epigenetic mechanisms.

These results are complex, perplexing, but possibly slight, and demand greater examination. Science is unfortunately prone to fashion, and many scientists are intrigued but anxious that the scrutiny being applied to these studies is not robust enough to justify the fanfare.

If the changes are permanent, then we’ve got big news. But given that in mice they have at best only lasted a few generations, the effects are intriguing but not revolutionary. Creationists cite epigenetics to assert that Darwin was wrong, and that epigenetics may show Lamarckian evolution – that is, acquired during life. It doesn’t, as the changes do not alter the DNA sequence on which natural selection acts. Even if one day we did show that epigenetic tags were permanently heritable, it would still only be a drop in the evolutionary ocean. Show me one robust example, and I’ll show you a billion that are straight-up Darwinian.

New age gurus such as Deepak Chopra cite epigenetics as a way of changing your life, under the false supposition that genes are destiny, and epigenetic changes brought on by lifestyle choices such as meditation “allows us almost unlimited influence on our fate”. Well, no: that sandwich you just ate has changed the expression of your genes too. Even the few inherited epigenetic changes we observe are not very predictable, let alone predictably positive. The Överkalix grandsons lived longer if their grandfathers lived through famine. But the granddaughters of women who had survived fallow seasons had lower life expectancy. Conclusion? Much more work needed.

Epigenetics is fascinating but still in its infancy. It’s not heretical, it won’t upend Darwin, or give you supernatural powers, but it is a necessary pursuit in our never-ending quest to unpick the inscrutableness of being. More, unhyped, work is needed, and mystical thinking is never welcome round these here parts.