How populations shape your genome
Your DNA is a diary of where your ancestors walked.
Migration and drift
Human genetic variation didn't arise randomly. It was shaped by migration, isolation, founder effects, and natural selection. A variant that's rare in one population might be common in another. That's why ancestry matters in clinical interpretation: the same variant can have different implications depending on the population context.
Why it matters clinically
When a lab interprets a variant, they often look at population databases like gnomAD. A variant that's common in your ancestral population may be less likely to cause disease than one that's vanishingly rare everywhere. Population genetics helps us separate signal from noise.
The limits of labels
Population labels are imperfect. Admixture, migration, and identity are complex. Genetic ancestry is one piece of the puzzle, not the whole picture. Use it to inform interpretation, not to oversimplify.