Sequencing Hitler’s genome teaches us nothing useful about his crimes

Some say that if you resort to mentioning Adolf Hitler, you will lose the argument. If you resort to sequencing Hitler's DNA to try to get more attention for your TV channel, I'd say you've just lost it.

And yet, the UK's Channel 4 did just that. Hitler's DNA: The Dictator's Planwhich will air this Saturday. I forced myself to watch it, so you don't have to.

DNA came from blood-soaked piece of cloth carved from the sofa on which Hitler shot himself in 1945, which is now in a US museum. The resulting genome has gaps due to the age of the sample, but the Y chromosome is said to match that of a male relative of Hitler, suggesting it is genuine.

If this had been done purely as an academic attempt to add a little to our knowledge, for example by finding out whether Hitler had a Jewish grandfather as rumored (according to DNA, he did not), perhaps it would have been ok. Instead, we have a sensational two-part documentary that claims DNA evidence will “change our understanding of Hitler.”

The problem is that this implies genetic determinism – that Hitler was somehow destined to do the terrible things he did because of his genes. To be clear, the documentary doesn't make that specific claim, but it comes pretty close – what else could “The Dictator's Plan” mean?

This is tantamount to saying that if we created many clones of Hitler, they would all end up killing millions too. This is not an experiment we can (or would ever want) to perform, but there are many clones in the world in the form of identical twins sharing the same DNA. Twin studies have been used to assess the extent to which all kinds of traits and conditions are due to genes rather than environment.

Now there is many problems with twin studiesNot least of all, twins typically grow up in the same environment, so genetic and environmental influences cannot be completely disentangled. Despite this, the highest twin-based heritability estimates for crime—probably the closest to being a genocidal dictator—are less than 50 percent. Therefore, there is no reason to think that most of Hitler's clones will be monsters.

Moreover, our understanding of the human genome is in its infancy. We still can't predict simple traits like eye color with 100 percent accuracy, let alone much more complex traits involving the brain's interaction with the environment.

What we can do is look for genetic variants that are statistically associated with a higher risk of diseases such as autism. People could then be given a “polygenic score” for each condition. The point is that receiving a very high polygenic score for autism does not necessarily mean that a person is definitely autistic. There are many reasons for this: environmental factors also play a role, the relationship between a trait and a variant may be spurious, we haven't identified all the important variants, and so on.

“Due to inconsistent associations and limited generalizability, it should be emphasized that the polygenic measure of autism in its current state has no clinical utility,” meta-analysis completed earlier this year.

According to the documentary, Hitler's genome ranks very highly for autism, along with mental illness, schizophrenia, bipolar disorder and antisocial behavior or psychopathy. He also scores above average on ADHD. But there has long been a history of claims that Hitler had similar mental disorders based on his behavior. Genetic evidence does not prove anything, and the diagnostic criteria for these conditions do not include genetic evidence.

But more than that, what if he actually had any of these conditions? Do these labels explain anything? As Cambridge University's Simon Baron-Cohen says in the documentary, the neglect and abuse Hitler suffered at the hands of his alcoholic father “are much more important in understanding why he grew up with hatred and anger.”

We are later told that traits associated with schizophrenia may be associated with creativity and lateral thinking, which may explain his political and military successes. Really? This is pure speculation.

In my opinion, this is the problem of analyzing Hitler's genome. You can make all these plausible-sounding connections to what we know about his personality and actions, but they could all be completely false. Moreover, it risks exacerbating the stigma already associated with conditions such as autism, schizophrenia and bipolar disorder.

This documentary refutes his own claims because much of it simply rehashes what we already knew about Hitler. The only new thing is the claim that Hitler had Kallmann syndrome, which affects sexual development. But the physical consequences of this condition vary widely, and we already have Documented evidence that Hitler had an undescended testicleso, again, history is more informative than genetics.

There is also a broader issue that this documentary addresses: the idea that Hitler was somehow uniquely evil and solely to blame for World War II and the Holocaust. But unfortunately, there is no shortage of genocidal and war-mongering dictators – and none of them could succeed without the support of many others.

Millions voted for Hitler, other politicians supported the laws that allowed him to seize power, and many officials helped implement the racist laws that led to the Holocaust. There is no need to appeal to genes to explain why many people try to become dictators – the more pressing question is why we allow them to do so.

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