Mariana Cook’s book, “Faces of Science,” portrays 77 scientists who have made many of the most important discoveries of our time. Each photograph is accompanied by a personal essay written by the scientists. The portraits in this online series are accompanied by excerpts from those essays. For more information, please visit Mariana Cook’s website: www.cookstudio.com.
I became interested in DNA because I wanted to know what life was. Even after I entered college, biology was not yet in any way explicable in terms of the laws of physics and chemistry. There was a gene, but we didn’t know how it could carry genetic information. The 1953 discovery of the DNA double helix let us immediately know how genetic information is stored. The double helix also revealed how genetic information is copied. Through separating its two strands, the information of parental strands is used to lay down the information of the new daughter strands with complementary sequences. When we found the double helix, we solved two big problems—what is genetic information, and how is it copied?
What we didn’t know (the third big question at the time) was how cells read genetic messages. Just knowing the structure of DNA wasn’t sufficient. We had to discover the cellular machinery that reads the genetic information of DNA. In doing so, we learned that the genetic information of DNA becomes copied into RNA chains of complementary sequences. These, in turn, are used as information molecules to direct the laying down of polypeptide chains of proteins. This exciting adventure story lasted 13 years, leading to the 1966 establishment of the genetic code