After the human genome was first analysed in 2001, doctors expected to rapidly discover which genes caused which diseases and which genes could predict specific illnesses. That didn’t happen.
It turned out that most diseases and conditions had multiple genetic factors involved. Researchers were downhearted and until very recently most doctors have proclaimed that data from DNA tests is almost worthless as a predictor of future health.
But suddenly this prospect is changing. There’s never been data available on as many people’s genes as there is today. And that wealth of information is allowing researchers to guess at any person’s chance of getting common diseases like diabetes, arthritis, clogged arteries, and depression.