One-Third of Gene Map Completed
by
Paul Recer,
AP Science Writer

2:04 PM EST; November 23, 1999; Washington, D.C. (AP) -- Government-supported scientists have sequenced one-third of the human genetic pattern and are on schedule to complete and verify the entire biological blueprint by 2003, officials said Tuesday. Dr. Francis Collins, head of the National Human Genome Research Institute, said that 1 billion of the 3 billion chemical base pairs in the human genetic pattern have now been identified, sequenced and published on a public database. By next spring, he said, a working draft of the entire human genome will be completed. It will take an additional three years to carefully verify the sequences to produce a final result that Collins said would be "accurate, assembled and mapped."

The human genetic pattern is a biological map laying out the exact sequence of 3 billion pairs of chemicals that make up the DNA in each human cell. The bases are composed of two of four chemicals -- thymine and adenine, or guanine and cytosine -- arranged in pairs along a coiled helix in the nucleus of each cell. The base pairs are sequenced in specific ways to create the 100,000 human genes. The genes, in turn, form the blueprint for the assembly of proteins and compounds that guide the form and function of cells and organs. Researchers believe that by identifying each gene and determining its effect, medical science will find new ways to treat or prevent birth defects and illnesses such as cancer and heart disease.

An international effort, called the Human Genome Project, started sequencing the genes five years ago. About 85 percent of the work is being done at five large centers: The Whitehead Institute in Cambridge, MA; Washington University School of Medicine in St. Louis; Baylor College of Medicine in Houston, TX; The Joint Genome Institute in Walnut Creek, CA, and the Sanger Center in Cambridge, England. The U.S. Energy Department funds the work at the California facility, and the Sanger Center is supported by the Wellcome Trust. The other three centers are supported by NIH. Some work in the project is also being done in government-supported labs in France, Germany, Japan, and China. Private laboratories are also sequencing the genome and some have claimed up to a billion base pairs already. However, experts said those companies are using a less precise method. The government-sponsored effort involves checking each sequence repeatedly by computer to ensure its accuracy.

Also, in contrast to the private labs, the government-supported labs are daily publishing completed sequences for free use by scientists worldwide. Some private labs plan to patent gene sequences in order to develop commercial health products. Officials said that of the 1 GBP (Giga [billion] Base Pairs) sequenced so far, 468 MBP (Mega [million] Base Pairs) are in final, verified form. An additional 665 MBP are in a working draft that will be further verified by computer. Both forms are useful to scientists, officials said. "During the early years of the project, much of the work involved developing technology to speed the sequencing and to enhance the accuracy," said Collins, "but in recent months the work has accelerated." "Most of the 1 GBP has been sequenced in the last seven months," he said.