Deciphering the Code of Life; December 1999; Scientific American Magazine; by Collins, Jegalian; 6 Page(s)

When historians look back at this turning of the millennium, they will note that the major scientific breakthrough of the era was the characterization in ultimate detail of the genetic instructions that shape a human being. The Human Genome Project-which aims to map every gene and spell out letter by letter the literal thread of life, DNA-will affect just about every branch of biology. The complete DNA sequencing of more and more organisms, including humans, will answer many important questions, such as how organisms evolved, whether synthetic life will ever be possible and how to treat a wide range of medical disorders.

The Human Genome Project is generating an amount of data unprecedented in biology. A simple list of the units of DNA, called bases, that make up the human genome would fill 200 telephone books-even without annotations describing what those DNA sequences do. A working draft of 90 percent of the total human DNA sequence should be in hand by the spring of 2000, and the full sequence is expected in 2003. But that will be merely a skeleton that will require many layers of annotation to give it meaning. The payoff from the reference work will come from understanding the proteins encoded by the genes.