Scientists turn modern biobanks into a new window on human evolution

Scientists are finding new ways to track human evolution by looking at modern biobanks. A recent study of over 72,000 Han Taiwanese participants demonstrates that large-scale health data is not just for medical diagnoses. By comparing genetic variations across different adult age groups, researchers identified patterns of ongoing natural selection that are currently shaping human genomes.

The findings were published in The American Journal of Human Genetics. The team examined over 500,000 genetic variants to see if they became more or less common as people aged. This analysis uncovered 168 variants that deviated from neutral expectations. Approximately 90 percent of these were rare variants that earlier studies often overlooked. Many of these are linked to serious health conditions like cancer, neurological disorders, and cardiovascular disease.

One significant discovery involves the BRCA1 gene. Researchers found a rare haplotype carrying 16 protein-altering variants that appears to be under purifying selection. This means the human population is naturally purging these harmful variants over time. Meanwhile, other parts of the same genes showed evidence of positive selection, showing how complex evolutionary trade-offs dictate genetic survival.

Another key finding involves pleiotropy, where single genes affect many different biological traits. Genes such as ATG9A and FADS2 showed significant impact on liver function, lipid metabolism, and bone density. These results suggest that natural selection often acts on genes that control multiple physiological systems at once. This insight helps clarify why certain genes remain focal points for human health.

This framework offers a path for precision medicine beyond the current bias toward European-ancestry data. As more nations build national biobanks, applying this evolutionary analysis globally could identify medically relevant variants specific to different populations. Human evolution remains an active process, and these tools allow scientists to read the genetic record while it is still being written.