HUMAN GENOME: Scientists Celebrate ‘Working Copy’ of Map
Two teams of scientists announced yesterday they have mapped a "rough draft" of the approximately 3 billion "letters" of DNA that make up the human genome, marking an important milestone in the ongoing effort to identify the genes responsible for human life and understand how they work. Although the genome map is incomplete and a tremendous amount of work remains in order to translate the findings into practical benefits, the work was hailed as extremely valuable to scientists interested in searching the genome for desired genes that could be studied to develop medical treatments or further our understanding of human development. The achievement was announced jointly by leaders of the Human Genome Project, an international consortium of academic centers, and Celera Genomics, a commercial enterprise located in Rockville, Md. (Wade, New York Times, 6/27).
Learning the A,T,G's
The genome is composed of 23 pairs of chromosomes, long strands of DNA molecules found in the nucleus of each human cell. The DNA molecules take the form of intertwined strands with "rungs" between them, each made of one of four possible bases represented by the letters A, T, G and C. Sections of DNA molecules comprise genes, which govern the production of the proteins that perform essential tasks in the human body and determine physical characteristics. It is the order of the rungs that scientists have spent 10 years and $2 billion deciphering. Working independently, the two teams have identified 97% to 99% of the genome "letters" and placed about 85% of those in order. Some gaps remain in the sequence -- including DNA segments that cannot be analyzed by existing equipment -- and many smaller segments of the genome must still be assembled in the correct order before the overall picture is complete.
More to Be Done
Although most of the genome has been sequenced, scientists still must find the 3% to 4% of the genetic material that comprise actual human genes. Estimates of the number of genes range from 38,000 to more than 120,000; the remainder of the material is thought to be superfluous "junk DNA" with no biological function. After identifying the genes, the next challenge will be to understand how they work in conjunction with each other and with environmental factors to influence human development, health and disease, and how to design treatments that use this information to correct or prevent undesirable traits or disposition toward disease (Weiss/Gillis, Washington Post, 6/27).
How Big Is This?
Is the mapping of the human genome the greatest scientific accomplishment of the past 100 years? Or is it instead just the beginning of a century of toil before its benefits can be applied? Headlines from around the nation paint varied pictures of the event's meaning:
- The Language of God (New York Daily News, 6/27)
- Scientists Put Together the Human Book of Life (Borenstein, Knight Ridder/Owensboro Messenger-Inquirer, 6/27)
- The Beginning of a New Science (Rosenberg/Mishra, Boston Globe, 6/27)
- Science Stands at Threshold of Gigantic Genetic Jumble (Angier, New York Times, 6/27)
- Now, the Hard Part: Putting the Genome to Work (Wade, New York Times, 6/27)
Want to Know More?
To read President Clinton's remarks on the announcement click here or type www.pub.whitehouse.gov into your browser. William Haseltine, CEO of Human Genome Sciences, will host a live, online chat at Washington Post.com on Thursday, June 29th at 3:30 p.m. Read tomorrow's American Health Line for complete coverage of the reaction and analysis following the Human Genome Project announcement.