"Human Genome Placed on Chip" read the headline this past October as the New York Times reported that three biotech companies have made thumbnail-size devices that can record the activity of all the genes in a sample of human tissue. Thus is fulfilled one of the promises of the Human Genome Project: by scanning the human DNA sequence, scientists can now guess which bits are the genes that are transcribed into RNA messages and then translated into functional proteins.
When the "final draft" of the sequence was released in April, many said that the string of three billion A, T, G and C bases in human DNA represents--choose your metaphor--the book of inheritance, the source code of cells, the blueprint for a life. But in truth, all these metaphors mislead.
This article was originally published with the title The Unseen Genome: Beyond DNA.