Researchers Decode Human Chromosomes 5, 16, And 19

"Three chapters in the reference book of human life are nearly complete," said Secretary Richardson. "Scientists can already mine this treasure trove of information for the advances it may bring in our basic understanding of life as well as applications such as diagnosing, treating and eventually preventing disease." Richardson made his remarks at the 25th Annual American Association for the Advancement of Science Colloquium on Science and Technology Policy in Washington, D.C.

"All involved in this great international labor of discovery are tremendously excited, delighted, and even a little surprised, by how swiftly it is now racing towards its wonderful, revolutionizing goals," said Dr. Elbert Branscomb, director of the Joint Genome Institute and chief scientist for the Energy Department's human genome program. "Of course, we are extremely pleased to have reached our draft milestone as part of that effort."

The human genome is the full complement of genetic material in a human cell; it contains instructions for making all the protein molecules for all the different kinds of cells of the human body - neurons in the brain, red blood cells, bone tissue, liver cells, etc. In decoding DNA, researchers determine the "sequence" or exact order of the individual chemical building blocks, or bases, that make up the DNA.

The three chromosomes sequenced by Department of Energy researchers contain more than 300 million base pairs, or an estimated 11 percent of the total human genome. To date the researchers have sequenced a working draft of the three chromosomes, leaving some scattered gaps in less gene-rich areas. Institute researchers will continue to improve both the completeness and accuracy of the genetic information as they produce the final sequence of the chromosomes over the next several years.

Chromosome 5 contains an estimated 194 million bases, or about 6 percent of the human genome. Disease-linked genes on this chromosome include those for colorectal cancer, basal cell carcinoma, acute myelogenous leukemia, salt-resistant hypertension and a type of dwarfism. Chromosome 16 contains about 98 million bases, or about 3 percent of the human genome. Studies have implicated genes on this chromosome in the development of breast and prostate cancer, Crohn's disease and adult polycystic kidney disease, which affects an estimated five million people worldwide. Half the affected people require dialysis or kidney transplant. Chromosome 19 contains 60 million bases, or about 2 percent of the human genome. Genes involved in repair of DNA damage as well as those associated with atherosclerosis and diabetes mellitus are located on chromosome 19.

The information on chromosomes 5, 16 and 19 is available freely without restrictions to researchers in academia and industry through the public database, GenBank. Details about the chromosomes' draft sequence are expected to be published this summer as part of scientific articles describing the entire draft sequence.

The Joint Genome Institute, established in 1997, is one of the largest publicly funded human genome sequencing centers in the world. Three of the department's national laboratories operate the institute as a consortium: the Lawrence Berkeley National Laboratory in Berkeley Calif., the Lawrence Livermore National Laboratory in Livermore, Calif. and the Los Alamos National Laboratory in Los Alamos, New Mexico. The University of California manages all three laboratories for the Energy Department. The department's Oak Ridge National Laboratory is analyzing the sequences computationally to identify the locations of genes within the sequences.

The Department of Energy began the Human Genome Project in 1986 to map and determine the complete DNA sequence of the human genome. The project's ultimate goal is to discover the 80 to 100,000 human genes on the 23 pairs of chromosomes and enable biologists to study them in detail. The publicly funded effort, now an international research project, divides responsibility for sequencing the chromosomes among the participating sequencing centers. Other participants include the U.S. National Institutes of Health and the Wellcome Trust in England which jointly announced in December the completion of the first final sequence for a chromosome, chromosome 22. The international project expects to complete the draft for the entire human genome in June, with a final sequence available on or before 2003. Last month, the international consortium completed the draft sequence for the human genome's second billion of three billion base pairs.

The Energy Department's role in the Human Genome Project arose from the historic congressional mandate of its predecessor agencies (the Atomic Energy Commission and the Energy Research and Development Administration) to study the genetic and health effects of radiation and chemical by-products of energy production. From this work grew the recognition that the best way to learn about these effects was to study DNA directly. The ability to analyze the entire human genome makes it possible to observe changes in DNA itself before they may result in disease as observed by traditional epidemiological research.

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ATTENTION EDITORS: Graphics on the human genome are available at http://www.ornl.gov/hgmis/graphics/slides/images1.html. Additional information on the three chromosomes and the Joint Genome Institute is available on the World Wide Web at http://www.jgi.doe.gov. Additional information on the Human Genome Project and the department's Human Genome Program can be found at http://www.er.doe.gov/production/ober/genome.html. and http://www.ornl.gov/hgmis.