A Crack In Creation: A Nobel Prize Winner's Insight into the Future of Genetic Engineering

by Jennifer A. Doudna

To transform the instructions contained in DNA into proteins, cells use a crucial—and closely related—intermediary molecule called ribonucleic acid, or RNA, which is produced from the DNA template via a process called transcription. RNA has three of the same letters as DNA, but in RNA, the letter T (for thymine) is replaced with the letter U (for uracil). In addition, the sugar that makes up the backbone of RNA contains one more oxygen atom than the sugar in DNA (hence the name deoxyribonucleic acid). RNA acts as a messenger, ferrying information from the nucleus, where the DNA is stored, to the outer regions of the cell, where proteins get produced. In a process called translation, cells use long strings of RNA that are produced by discrete segments of DNA—stretches of code called genes—to construct individual protein molecules. Every three letters of RNA, when read together, equal one amino acid, and amino acids are the building blocks of proteins. Genes and their corresponding protein products differ from one another by the sequence of nucleotides (in genes) and amino acids (in proteins). This overall flow of genetic information—from DNA to RNA to protein—is known as the central dogma of molecular biology, and it is the language used to communicate and express life. The size of a genome and the number of genes it contains varies widely across different kingdoms of life. Most viruses, for instance, have just a few thousand letters of DNA (or RNA, since some viral genomes...