Where Will Genetic Knowledge Lead Us?
Deciphering the human genome has provided insights into the nature of humanity, our relationship to the world, and our future. We now have the set of instructions that specifies human development--how each of us progressed from a single cell (a fertilized egg) to an adult human comprising a hundred trillion cells of thousands of different types. So what comes next?
The genome's language is DNA, whose alphabet has just four different letters: G, C, A, and T. But the genome contains three billion of these letters. The Human Genome Project translated them into a `Book of Life,' that consists of 500 volumes, each with 1,000 pages averaging 1,000 six-letter words per page. Operationally, the human genome is composed of one long sentence of three billion letters cut into 24 pieces--chromosomes--that range in size from 45-280 million letters.
In a book, words are collected into sentences, sentences into paragraphs, and paragraphs into chapters. Each level provides a higher, more coherent level of meaning. So, too, with the human genome. DNA's words are genes, which encode proteins--the molecular building blocks of life. Genes and proteins are, in turn, gathered into the biological systems-- heart, brain, kidneys, and so forth--that execute the functions of life.