Your Genes Programmed by your Ancestors’ Terror

One of your ancestors had a terrifying experience? New research shows your genes might have a memory of this terrifying experience built into them, and you may fear the same thing happening to you.

But that’s now how genes should work, is it?

To understand this, we’ll begin by considering identical twins, who are born with identical genes.

Over time, their bodies and behaviors become increasingly different, more so if they grow up in different environments, having different experiences.

What happens to us in life changes the way our genes behave – this is called gene expression. What you do, what you eat, how you exercise, even the music you listen to alters your gene expression.

There’s no doubt that terrifying experiences also change our gene expression. This is accepted science. The behavior of the genes in our bodies changes with our experiences.

In technical terms, your inbuilt, inherited genes, called your genotype, are influenced by gene expression to determine your phenotype. Your phenotype is YOU – the way you develop, and behave, your internal biochemistry, the way you think, and what you do with your time each day.

It’s already well-known that if one family member has a phobia, then the levels of this phobia among first-degree family members will be much higher than average, by a factor of more than x10.

More recently, scientists have claimed that terrifying experiences do not only affect your phenotype, they actually get built into your genes and can be passed on as an inherited fear to your offspring and generations to come.

Barry Dias and Kerry Ressler from Emory University School of Medicine exposed mice to fearful experiences (electric shocks) while there was a smell of cherry blossom around.

We’d normally expect this would alter the mice’s gene expression, affecting their behavior – their phenotype. We would not expect it would fundamentally change their genotype, their basic genetic code that would be passed on to future generations.

BUT it turns out that the mice’s offspring and the offspring’s offspring were still fearful of the scent, even though they had never smelled it before and had no reason to fear it.

The brains of the parent mice were found to have been changed by their experiences, and the offspring also showed the same changes to their brains.

This is evidence that a parent’s experiences can be written into the parent’s genetic code, then passed on to the children and later generations. If an ancestor of yours had a bad experience, you might also fear that experience, even if you have no reason to fear it from your own experiences.

Your own fears, such an unusual terror of spiders, heights, open spaces, or closed spaces, etc, may come from something that happened to a parent, grandparent, or someone further back in your family tree.

This is a rather extraordinary claim, and does not fit with our current understanding of evolution by natural selection.

It’s a basic tenet of science that the more extraordinary the claim, the higher the level of proof that is required. So don’t go expecting that the evidence from this single study will be enough to change the textbooks. More studies will be required for that to happen.

All the same, it’s very interesting, and science does thrive on interesting new phenomena.

Much more speculatively, the research also raises the possibility that other memories of our ancestors could have been built into their genes and passed on to us.

If this were true, claims of people to have memories of previous lives may need to be revisited… but this really is entering the realms of fantasy, isn’t it?