A drop of blood on filter paper preserves not only cells but also a record of what has been happening to the body over the past few months. That record is not in the genes but on them: the chemical marks cells attach to DNA change with food, stress, illness and age. Scientists have learned to read this archive tape to reconstruct a picture of health without repeated trips to the lab.
Previously, methylation was used to predict only individual markers: dozens of proteins or metabolites. The new work is the first to cover three domains at once: clinical blood tests, metabolites and proteins. The researchers trained 1694 models on data from 4418 people who had all three types of data collected at the same time. For each biomarker they selected the most informative stretches of DNA and then built a prediction.
Testing on seven independent groups, including pediatric and population cohorts, confirmed that the models work across different people. What is more, the predicted values are often more strongly linked to disease than the measured biomarkers themselves. For example, the proxy for urate level pinpointed sex: men have higher levels, which matches known biology.
The archive tape turned out to be more than a copy of current tests. It integrates a signal over a long period, so it reflects the risk of chronic disease better. Today such proxies can be used as inexpensive screening: one blood draw instead of many costly tests. In the future this will make it possible to track health from biobank samples or even at home.
The proxy for urate accurately predicted sex: men have higher urate levels, which matches the known sexual dimorphism.
In the series Altered Carbon, consciousness is transferred between bodies, and here DNA methylation acts as a "backup copy" of biological state, making it possible to reconstruct a picture of health from a single sample.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.