Gene switches once dismissed as ‘junk’ now seen as key to disease
Among the many mysteries of human biology is why complex diseases like diabetes, high blood pressure, and psychiatric disorders are so difficult to predict and, often, to treat. An equally perplexing puzzle is why one individual gets a disease like cancer or depression, while an identical twin remains perfectly healthy. Now scientists have discovered a vital clue to unraveling these riddles. The human genome is packed with at least 4 million gene switches that reside in bits of DNA that once were dismissed as ‘‘junk’’ but that turn out to play critical roles in controlling how cells, organs, and other tissues behave.