illustration representing discrete nucelotides in sequence on dna double helices - 核甘酸 幅插畫檔、美工圖案、卡通及圖標
conceptual image of a telomere. a telomere is a region of the dna sequence at the end of a chromosome. - 核甘酸 幅插畫檔、美工圖案、卡通及圖標