The question “What makes us who we are?” also concerns Christoph Bock, bioinformatician at the CeMM – Research Center for Molecular Medicine of the Austrian Academy of Sciences (OeAW) and member of the Young Academy. In this interview, Bock explains how tightly intertwined genetic predispositions, external influences and sheer randomness are. He describes why gene analyses reveal only probabilities, how national sequencing initiatives like “Genome of Europe” may fundamentally transform medicine, and how modern genomic diagnostics are already paving the way for more precise therapies.

From body height to life expectancy

Mr. Bock, what makes us who we are – genes or environment?

Christoph Bock: This classic opposition falls short. We need to consider four factors: genes, environment, gene–environment interactions – and chance. When comparing pairs of identical and fraternal twins who grow up in similar environments but differ in genetic similarity, you can estimate the maximum influence of genes. For example, body height is about 90 percent genetically determined in twin studies.

Some genes only matter when the appropriate environment is present.

However, in the general population, the environment plays a much greater role than this number suggests. For instance, average body height in Austria has increased by about ten centimeters from 1900 to today – not because the genes changed, but because of nutrition and fewer severe childhood illnesses, thanks to better hygiene and widespread vaccination.

And what exactly are gene–environment interactions?

Bock: Some genes matter only when the appropriate environment exists. For example: certain genetic factors make it very difficult to quit smoking – but if you never start smoking, the problem doesn’t arise. Our genes can also influence our environment or surroundings. Example: In the US, a young man taller than seven feet (about 2.13 metres) has over a 10 percent chance of playing in the NBA. Other traits are far less genetically determined. Life expectancy has a heritability of only around 30 percent in twin studies because many causes of death – accidents, infections, cancer – depend heavily on random events.

Hitler’s Genes: Statistics and Speculation

A recent TV documentary analysed Adolf Hitler’s DNA to draw conclusions about his personality. To what extent can we infer behaviour from a person’s genes?

Bock: First of all: this analysis has not yet been scientifically published; it has only been described in a TV documentary. From an academic standpoint, the correct order would have been to publish the data and the paper first, and then the documentary. Therefore, I can only respond very generally. A detailed scientific assessment must wait until the details are published.

Life expectancy has a heritability of only about 30 percent in twin studies.

Certain aspects of behaviour have a strong genetic basis. For some psychiatric illnesses such as schizophrenia, heritability is about 80 percent in twin studies. For clinical depression, it is still around 40 percent. Everyday traits also have genetic components – curiosity, caution, for instance. A surprising example is sexually transmitted infections like HIV: a partly genetically influenced risk-taking tendency leads to significantly increased infection rates. But all these are statistical statements that describe differences in the probability of certain traits and are only meaningful for the average of a large group. Applied to a single person, it becomes pure speculation.

Europe’s Genes

You played a major role in shaping Austria’s first human genome project. How did it come about?

Bock: When I arrived at CeMM in 2012, genetics in Austria was a sensitive topic. Milk cartons proclaimed in large letters “GMO-FREE,” and only on closer inspection did it become clear that this referred to the feed – not the cows themselves. But already then it was clear that modern medicine would not work without genomic analyses.

Today, genome sequencing is clinical routine, especially for rare diseases and in cancer medicine.

So we didn’t want to start genome sequencing with seriously ill individuals; instead, we first wanted to explore what can be learned from personal genomes together with healthy volunteers. The first participant was CeMM Director Giulio Superti-Furga. More than a thousand volunteers signed up, but due to cost constraints we could sequence only 20 at the time. Genom Austria sequenced, analysed and published the first personal genomes in Austria – openly on the internet and closely guided by leading bioethics experts. We also conducted an educational outreach project, discussing the possibilities and limits of genome research with young people.

What is the status of Genom Austria today?

Bock: Today, genome sequencing is clinical routine, especially for rare diseases and in oncology. But an Austrian reference genome was still missing – most existing data comes from the UK, the US, Iceland, Germany, and other countries. Thanks to an EU initiative, the “Genome of Europe” project was launched last year, which aims to sequence 100,000 genomes from people across the EU. Each country contributes proportionally to its population size. For Austria, that’s just over 2,000 genomes. Nearly half will be sequenced at CeMM, and the Medical University of Innsbruck coordinates the project. Thus – ten years after the start of Genom Austria – a genomic map of Europe is finally emerging, with a substantial Austrian contribution.

What We Gain from Genome Sequencing

What advantages does genome sequencing offer people in Austria?

Bock: Genome sequencing is especially valuable for individuals with rare genetic diseases: although about ten percent of the population is affected, the cases are spread across thousands of different diagnoses, so the underlying cause often remained unclear in the past. Today, sequencing enables a rapid and precise diagnosis for about half of those affected – sometimes leading to new, targeted treatment options. Genomic analysis also plays an important role in cancer medicine. Since tumours are genetically altered body cells, sequencing can identify specific vulnerabilities against which tailored therapies can be used. For some cancers this is already standard practice and is set to expand further.

Genome sequencing contributes to public health.

Beyond that, some people use genetic tests for ancestry research or to determine personal traits. This can provide insights into one’s origins but also carries risks – such as the discovery of unexpected family relationships or genetic information one might not have wanted to know. And on a societal level, genome sequencing supports public health. Since the COVID-19 pandemic, for example, wastewater from treatment plants has been genetically screened for dangerous viruses and pathogens.

In short: Genome sequencing improves diagnoses, enables personalised cancer therapy, can support ancestry research and helps detect pathogens early.