Life Science: Understanding the Human Genome Project
DNA, or deoxyribonucleic acid, is a chemical compound containing the genetic instructions for all life, including human life. DNA is made up of four chemical units: adenine, thymine, guanine and cytosine, represented by the letters A, T, G and C. The human genome has over 3 billion of these DNA “letters.” The order in which a person’s DNA comes together helps determine their physical traits, such as whether they have blue or brown eyes, whether they’re left or right handed, and sometimes, it determines their tendency to certain diseases. Sequencing a person’s genome means mapping out that person’s unique DNA blueprint.
The Human Genome Project was an international research partnership that attempted to create a map, or directory, of most human genes, with the goal of understanding human development and how genetic mutations can result in disease.
In America, the Human Genome Project was funded by the U.S. National Institutes of Health (NIH) and the Department of Energy. The 15-year group of projects officially started in 1990. U.S. government labs collaborated with international scientists to sequence, or map, 95 percent of the DNA in human cells. The International Human Genome Sequencing Consortium was made up of 20 scientific labs, research centers and universities from all over the world. The project was projected to be finished in 2005, but the Consortium announced a “finished” version of the human genome sequence in 2003. Although about 1 percent of the human genome remains unsequenced, the human genome is now essentially mapped. The information is publicly available for scientific and medical research.
One of the main goals of the Human Genome Project was to discover the genetic causes of disease and to use that information to produce targeted treatments, or even cures for common diseases. Researchers hoped that the information would lead to more accurate diagnostic tests for hereditary diseases and would aid in the development of targeted drug therapy to match a patient’s genetic makeup. Researchers have been surprised to find that many of the medical advances they expected have been slow to materialize, due in part to the discovery that many diseases have complex genetic causes. However, the Genome Project has advanced scientific understanding of the biological building blocks of life, yielding information that will be the basis for a steady stream of new research projects.
Sequencing the human genome was too huge a task for any one organization, so it was broken down into pieces and distributed to research centers around the world. Scientists identified the correct order of the massive genome map by identifying unique marker sequences throughout. Then they broke the genome into sections. Different sections were taken by various research facilities around the world. Scientists took the DNA in their assigned sections, copied it and broke the copies down into fragments. Then the researchers mapped the DNA sequence of these fragments and reconnected them to other fragments, in the correct order, with the help of computer technology. Eventually almost all of the human genome was mapped in this way.
The primary goal of the Human Genome Project was for medical researchers to use the DNA map to learn the genetic causes of common diseases and to develop new targeted therapies. Although science has learned a great deal more about the human body because of the Human Genome Project, this new DNA map has not resulted in the hoped-for cures--or at least, not yet. However, the project has made possible benefits such as: identification of genes associated with certain diseases; faster, more sensitive diagnostic tests; and the potential for “custom drugs” that are tailor-made for a patient’s particular genetic makeup. Precise DNA mapping also has implications for forensics and justice, energy and a host of other applications.
From the beginning, ethicists were concerned about the implications of mapping the human genome. Many feared that gene mapping would quickly open a Pandora’s Box of moral and ethical dilemmas. For example, some indigenous groups are concerned about DNA collection methods and especially, the possibility that their cell lines will be patented and commercialized. They complain that they seldom see any economic benefit from the information harvested from them.
Gene testing can tell a patient if they’re at higher risk for certain inherited diseases, but some worry that the information might be obtained by insurance companies and used to discriminate against high-risk policyholders. Gene testing can also tell parents if their child will be born with Down’s syndrome, but not how severe it will be. The ethical dilemma about what to do with the new information is an ever-present concern.
The Human Genome Project has been hailed as one of the biggest breakthroughs in the history of science, but many of its anticipated benefits are still years away. Some researchers have drawn the conclusion that the project is not yet the solution to many diseases and problems that plague mankind, but one of the bases on which those solutions will be built.
Written by Joanna Cliff