Most people would be classified as having a high genetic risk for around three common diseases, including diabetes, cardiovascular disease and schizophrenia. But most of us are not destined to become ill, according to a new study. It is that genetic risk is far more common than the disease itself — and the two should not be confused.

Published in the journal Genome Medicine on October 22, the study set out to describe what a typical human genome looks like and how much genetic variation people carry, including variations associated with disease. Researchers led by the University of Exeter analysed genetic data from nearly one million people in the UK Biobank and the US All of Us research programme. Their findings offer a useful lesson in how to interpret genetic tests, and why a concerning result on a DNA report is not necessarily a prediction of what will happen to your health.

The study is significant because it offers a useful corrective to the idea that our DNA can neatly predict our medical future.…