Friday, March 14, 2008

What Are Genetic Researchers Really Trying to Figure out?

The Human Genome Project recently announced that they had sequenced all of the human chromosomes — about three billion bases long. In itself, this is a huge achievement, but knowing the sequence doesn't tell researchers what the 30,000 to 50,000 genes actually do in the body. Their next step is to figure out what the genes do, and what role these genes may play in disease

Once researchers know which genes are involved in a disease, they can develop a test to screen people who are at risk and also start looking for a cure. A diagnostic test by itself will not cure the disease, but it can help identify high-risk people who may require more intensive screening or preventative action. Knowing what genes cause a given disease can also help researchers understand what goes wrong in that disease, which can help drive the search for drugs that counteract the problem

All Discoveries Are not of Equal Importance
When newspapers announce that a gene has been discovered for a certain disease, it can really mean a number of things.
  • Finding the gene: Sometimes, researchers have identified a gene that definitely causes a disease, such as the discovery of the gene for hemophilia or cystic fibrosis. Such a finding does not necessarily mean that researchers can cure the disease, or that a genetic test is immediately available, but it does mean that the medical community may be closer to an possible cure.

  • Finding one of many genes: Other times, researchers have discovered a gene that plays a role in a small subset of people who get a common disease, such as the genes BRCA1 and BRCA2, which are the cause for some people's breast cancer. Again, finding these genes puts researchers one step closer to a cure or genetic test that can help some people with the disease.

  • Finding a gene in animals: One way to understand gene function in in humans is to find and manipulate a gene that causes an animal — such as the mouse or fruit fly — to show symptoms similar to a human disease. Animals have genes that are very similar to our own, so these discoveries help point researchers to the biological function of a human disease gene. However, it is a long path from finding a gene in flies or mice to finding a genetic treatment for the human disease.

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