Watson and Crick advanced the double helix structure model of the DNA in 1953. The DNA is made up of two pieces of nucleotide chains, which is double helix structure with complementary pairing of the bases and winding each other.

• 1953年Watson和Crick提出了DNA的双螺旋结构模型：DNA分子由两条多核苷酸链组成，这两条核苷酸链通过碱基的互补配对相互缠绕形成一种双螺旋结构；