Being as an important hereditary substance, DNA has the double helix, the two bonds composing the double helix are mating and connecting with each other through the purine and the pyrimidine.

• 作为重要的遗传物质,DNA为双螺旋结构,组成双螺旋的两条链由嘌呤和嘧啶通过氢键配对联系。