Weekly Online Lesson Online Lesson Archive Grade Level: 8-12 Subject: Biology

Mapping the Human Genome

The International Human Genome Project and Celera Genomics Corporation both announced on June 26, 2000 the completion of a "working draft" sequence of the human genome — the genetic blueprint for human beings. This major milestone involved two tasks: placing large fragments of DNA in the proper order to cover all of the human chromosomes, and determining the DNA sequence of these fragments.

The assembly currently consists of overlapping fragments covering 97 percent of the human genome, of which sequence has already been assembled for approximately 85 percent of the genome. The sequence has been threaded together into a string of As, Ts, Cs, and Gs arrayed along the length of the human chromosomes — 3.2 billion molecules (letters) long.

The sequence represents only the first step in the full decoding of the genome, because most of the individual genes and their specific functions have yet to be deciphered and understood. This research has begun, and tens of thousands of genes have already been identified, including some related to deafness, kidney disease, breast cancer, hereditary skeletal disorders, hemorrhagic stroke and diabetes, thus advancing the work of researchers worldwide at a rate that would have impossible without this knowledge.

In this week's online lesson you will learn more about the work of human genome sequencing and what it means for the future of medicine and biology.

Decoding the Human Body

Unless you have completed some pretty serious study of molecular biology, the ramifications of having a nearly complete sequence of the human genome may take a back seat to questions like, "What's a gene?" For some critical interpretive reading that will set the stage for the remainder of the lesson, read the Newsweek article "Decoding the Human Body." Why did the Human Genome Project begin with the Department of Energy? What will it mean to know the complete human genome? What are some of the ethical issues of human genome research?

Also read A Genome Milestone, which features a great interactive presentation called Mapping DNA. This gives a concise explanation of how researchers sequence DNA.

National Human Genome Research Institute

Now that you have some important background, visit the Web site at the center of all the genomic action: The National Human Genome Research Institute. Start by reading about the Human Genome Project, which is of course the subject of this lesson. Read what the project entails, when it began, and what its goals are.

Most of the resources on this site are for researchers, but a few are for learners like you. For example, in the Education and Outreach section you will find a gallery of Genetic Illustrations. Click the link to see an illustration of each term. Try it. Click DNA (detailed) to see a large color illustration of the base pairs that form the double-helix of DNA. You can save any of these illustrations in PDF format for later viewing; just click the link below each illustration.

Another great reference tool for learners is a Talking Glossary of Genetics. When you enter the glossary, scroll down and choose a term from the list (chromosome, for example). Read the definition, see the illustration, or listen to an expert give a detailed explanation (requires RealPlayer).

To Know Ourselves

You will find good basic information about the Human Genome Project by reading the online publication To Know Ourselves. There are a number of topics you can explore, among which you should read The Genome Project—Why the DOE? and Introducing the Human Genome. To consider some of the ethical questions arising from genetic research, read Ethical, Legal, and Social Implications.

Primer on Molecular Genetics

The U.S. Department of Energy hosts a Primer on Molecular Genetics, another guide with basic information about genetic science and the Human Genome Project. Choose a topic from the index, or begin with the Introduction covering DNA, Genes, and Chromosomes. If you would like to know specifically about the technologies of sequencing DNA, read the Sequencing Technology topic.

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