Human Genome

What mapping really means.

Medically Reviewed by Annie Finnegan
3 min read

June 27, 2000 -- Since the announcement of the rough draft of the human genome, the metaphors describing the special accomplishment have been nearly as plentiful as genes yet unmapped: Lewis and Clark, man-on-the-moon, the book of life, just plain phenomenal.

As accomplishments go, all that hyperbole may fall short. But in the meantime, there's still work to be done to truly realize all the bounty of the mapping of the human genome.

Stephen T. Warren, PhD, professor of human genetics at Emory University School of Medicine in Atlanta, tells WebMD there's "still a substantial effort that needs to be carried out, so I think the important thing people need to realize, it was a lot of work to get the sequence, but that alone isn't going to tell us much until we do another huge amount of work."

By 2003, the Human Genome Project aims to map the entire human genome to almost 100% accuracy. The private company that has also mapped the genome, Celera Genomics, already claims to have mapped 99% of the genome.

Craig Venter, president of Celera, says the next step in the project is the "interpretation phase" where we "discover what it all means."

Part of that discovery will involve cataloguing substances that help determine differences in people. Those differences may lead to some of the earliest benefits from the current "rough draft" of the genome.

By pinpointing the differences in people, doctors may be able to prescribe medications they know will work, instead of the hit-or-miss method currently in use. "You could speed up the therapy right away, you choose the drug that you know has the high likelihood of working right off the bat without any trial and error," Warren tells WebMD.

Although thousands of genes have been identified, it's still unknown how many genes there are yet to be discovered. Some estimates range beyond 100,000, though most are below that.

After finding the genes, scientists then need to find out what that gene does -- in other words, what protein does it make and how does it affect the body. A gene basically tells the body to manufacture a certain protein that subsequently has a special function within the person.

Next, of course, is using that information. Warren says "having any target [for the medication to work towards] is better than the way most drugs are really designed, which is pretty much hit and miss." If the protein the gene encodes can be isolated, and if that protein is involved in illness, then a drug can eventually be developed against that specific gene or protein.

Tailoring drugs to people is decades away, but new drugs based on the recently released raw material could start benefiting people in just over a decade, according to Warren.

Another headline-grabbing aspect of the human genome is the possibility of being able to prescreen people for the potential likelihood they may get a certain disease. This prescreening could accelerate in the near future.

That information could lead people to take pre-emptive action against a disease, especially one like heart disease or type 2 diabetes, that might have some environmental causes. For other diseases, without a known cure, the benefit is harder to define: "What's the advantage to knowing you're going to get Parkinson's disease, or [multiple sclerosis], or Alzheimer's disease, when you're 15 years old?" Warren asks.

The mapping of the human genome is far ahead of schedule, and there's the possibility that similar advances might come about because of future innovations. For instance, IBM is working on a supercomputer called Blue Gene which may decipher some of the mystery behind how proteins work.

This "computational biology," or "bioinformatics," as Warren calls it, could collect information "without having to do the experiment, ... then to design a drug, for example, you may not have to solve the structure of the protein in the laboratory, you can make a reasonable prediction of the structure in the computer."

There are even other "spin-offs." For instance, using the current technology, the genome of rice has nearly been mapped, and this could have "a lot of implications for world hunger," Warren tells WebMD.

"One of the things is," he says, "we can't even anticipate or contemplate all the things we can do with this information; there may be things that are incredibly important that nobody's given a lot of thought to."