New study into ‘heritability’ shows that 50% of the variation in human lifespan could be down to genetics New study into ‘heritability’ shows that 50% of the variation in human lifespan could be down to genetics Some people who live to a great age put it down to an evening tot of whisky, others to staying out of trouble. Now scientists think they may have unlocked a key secret to long life – quite simply, genetics. Writing in the journal Science , the researchers described how previous studies