Instanz: TeilenTeilen:Gene Activity in Blood Fluctuates More Than Expected – And That Has Consequences for MedicineDr. rer. And yet, at the level of gene activity, the molecular picture can look surprisingly different. Season matters: the study identified more than 4,000 genes that shift their activity systematically between winter and summer. A January blood draw and a July blood draw capture different biological states of the same individual." A substantial share of what clinical studies have interpreted as disease-associated variation in gene activity may, in fact, be ordinary physiological fluctuation.