The Human Genome Project began in October 1990. The goal of the project is to sequence the entire human genome (all the DNA in a cell). The potential benefits of this information are numerous. In the area of medicine, nearly 3,000 human diseases have been identified as having a genetic link. By sequencing the human genome, it may be possible to improve disease diagnosis, detect genetic diseases earlier, and develop new drugs and gene therapies. Other potential benefits include: accurately assessing risks due to chemicals and other environmental factors; increasing knowledge about human evolution and migration; identifying individuals who are crime or disaster victims; and establishing the guilt or innocence of suspected criminals.
The term genome refers to all of the genetic material contained in an organism. Genetic material is deoxyribonucleic acid, abbreviated DNA. DNA exists as a double-stranded, spiral-shaped molecule. The molecule is often called the double helix. The molecular building blocks of DNA are nucleotides. Each nucleotide is composed of deoxyribose (a type of sugar), a phosphate group, and one of four nitrogen-containing bases. The nitrogen-containing bases are adenine, thymine, cytosine, and guanine; these names are used to identify the nucleotides.
Each strand of DNA is built from a chain of the four nucleotides. The strands are complementary, which means there are set pairings between nucleotides at each position along the double helix. Adenine only pairs with thymine, and vice versa; cytosine only pairs with guanine, and vice versa.
To meet the goals of the Human Genome Project, it will be necessary to identify which nucleotide pair occupies each position along the double helix. The entire human genome contains approximately three billion base pairs. At the outset of the Human Genome Project, scientists estimated that it would take 15 years to sequence such a vast amount of information.
Scientists first began to consider the possibility of pursuing the project in 1986. In the United States, the National Institutes of Health and the U.S. Department of Energy drafted a plan for the Human Genome Project by 1988, and work began in 1990. Similar efforts were underway in other countries, such as France, Britain, and Japan. In order to coordinate these efforts, an international research group was created. This group is called the Human Genome Organization (HUGO) and its primary purpose is to coordinate the worldwide collaboration. As of the mid-1999, HUGO included more than 1,000 laboratories in 50 countries.
At the outset of the project, researchers concentrated on building a detailed map of each human chromosome. The human genome is divided into a total of 46 chromosomes, including the sex chromosomes, X and Y. Chromosomes are distinct bundles of genetic material which are organized into 23 matching pairs. Each parent contributes 23 chromosomes to a child. The end result is that the child has two copies of each chromosome, for a total of 46.
On each chromosome, the DNA is divided into units called genes. In general, each gene codes for a specific product, such as a protein. The human genome contains approximately 100,000 genes. All chromosomes carry a characteristic set of genes. For example, the gene that codes for the enzyme, glucose dehydrogenase, is always found on chromosome 1. It doesn't matter whose genetic material is examined; the gene for that enzyme will always be found on the same location on chromosome 1.
Genes and other well-characterized DNA segments are used as genetic markers. Genetic markers serve as sign posts over the entire genome. As of 1995, researchers had created a map of the genome that contained about 15,000 markers. However, this accomplishment is a small part of the overall sequencing effort; the average distance between markers is two million base pairs.
Since 1995, researchers have made great progress in identifying those base pairs, aided in large part by advances in laboratory techniques. Because of this success, it is estimated that a first draft of the human genome will be completed by the spring of 2000, five years ahead of schedule.
Alongside the scientific advances, ethical, legal, and social issues of genetic research have also been incorporated as a distinct research area within the Human Genome Project. Several areas of concern have been identified such as privacy and confidentiality, the potential consequences of genetic testing, and who should have access to individuals' genetic information. Other concerns include potential misuse, ownership and control, and fair use of the information.
The genetic techniques that were developed for the Human Genome Project have been applied to the Microbial Genome Project, started in 1994. This project focuses on the genomes of bacteria and opens possibilities in the areas of energy production and environmental clean-ups. In the area of agriculture, advances in genetic research may lead to crops with better resistance to disease, insects, and drought. Crops may also contain plants with more nutrients. Research is being done to genetically alter plants so that they contain vaccines that would protect people against certain diseases. Animal research is geared toward developing healthier and more productive farm animals.
The Human Genome Project is not the only group working on genetic sequencing, both of humans and of other organisms. In May 1998, J. Craig Venter, a scientist from the non-profit Institute for Genomic Research (TIGR), described a new project on the human genome. It was a joint venture with the instrument company, Perkin-Elmer. He claimed he would complete the sequencing of the human genome by 2001 for a cost of $200-250 million. Although Venter plans to make information available to scientists, he will also patent 100-300 genes and charge for the use of databases. His technique is called whole-genome shotgun sequencing. First, the DNA is broken into thousands of fragments. Then, automated DNA sequencing machines read the read the base pairs at the ends of the various fragments. Finally, the information is fed into a computer that matches overlapping fragments. Although this technique leaves gaps, Venter maintains they are in repetitive areas of DNA that are not of interest. TIGR has already succeeded in sequencing the genome of a number of microorganisms, including the bacteria that cause syphilis, ulcers, and Lyme disease.
This is the complete article, containing 1,007 words
(approx. 3 pages at 300 words per page).
