1960 … DNA- now with sparkly stars! By x-ray delta one

One becomes two: this is the essence of life. Biologists now believe that the key to this process inside the cell  is the long-chain molecule known as deoxyribonucleic acid, or DNA.  At left is an infinitesimal portion of a “model” of DNA suggested in 1953 by James Watson and Francis H.C.Crick. It consists of two spirals and intertwining chains, who’s various molecular sub units are represented by colored shapes. Bridging the chains, like rungs on a ladder, are pairs of molecular sub units called “nucleotides”, which are essential to replication. The whole is so constructed that if the two chains are pulled apart, separating the paired nucleotides,  each chain  will contain all that is necessary to direct the recreation of the missing half.  In this way, one  molecule of DNA can become two-and life can go on.