Pharmacogenomics is a new word that is being used by scientists and drug developers. It describes the idea of tailoring drugs to patients, whose individual response can be predicted by genetic fingerprinting. A better understanding of genetics promises a future of precise, customized medical treatments.

Prognosis—Diagnosing ailments more precisely will lead to more reliable predictions about the course of a disease. For many diseases, such genetic information will help patients and doctors weigh the risks and benefits of different treatments.

Prevention—Once scientists figure out what DNA-sequence changes in a gene can cause disease, healthy people can be tested to see whether they are at risk for developing that disease. In many cases, this advanced warning can be a cue to starting a vigilant screening program, to take preventive medicines, or to make diet or lifestyle changes that might prevent the disease altogether.

Newborn screening—A particular form of predictive testing, newborn screening,

Carrier screening—For some genetic conditions, people who will never actually fall ill from it themselves can pass a disease to their children. Some couples choose to be tested for this risk before they marry, especially in communities where a feared childhood disease is particularly common. This form of screening has been  used for years.

Gene therapy—Replacing a misspelled gene with a functional one has long been an appealing idea. Small groups of patients have undergone gene therapy in clinical trials for more than a decade, but this remains an experimental treatment. Eventually, it is likely to become a common treatment for some conditions.

Gene-based therapy—Great medical benefit will likely be derived from drug design that is guided by an understanding of how genes work and what exactly happens at the molecular level to cause disease. However, researchers are optimistic that a more precise understanding of the underlying causes will lead to better therapies. In many cases, instead of trying to replace a gene, it will be more effective and simpler to replace the protein that the flawed gene gives rise to. Alternatively, it may be possible to administer a small molecule that interacts with the proteins, as many drugs do, and changes its behavior.

Instead of having to rely on chance and screening thousands of molecules to find an effective drug, which is how most drugs we use today were discovered, scientists will begin the process of drug discovery with a clearer notion of what they're looking for. And because rationally designed drugs are more likely to act very specifically, they will be less likely to have damaging side effects.

All living things encountered to date depend crucially on the activities of an unusual and complex family of molecules called proteins. There are hundreds of thousands of different kinds of proteins, and they work together in large groups to carry out almost every biological function.

Furthermore, all living things encode the recipes to create these thousands of different proteins in another unusual and complex family of molecules, the nucleic acids. There are two distinct kinds of nucleic acids, the deoxyribonucleic acids (DNA) and the ribonucleic acids (RNA), which play somewhat different, but related roles.

The relationship between nucleic acids and proteins is so important to modern biology that it is called The Central Dogma. The Central Dogma itself is relatively simple, although the chemical mechanisms underlying it are not.

The Dogma states that DNA molecules contain information about how to create proteins; this information is transcribed into RNA molecules, which, in turn, direct chemical machinery which translates the nucleic acid message into a protein.

The Central Dogma means that the flow of information is one-way:

from DNA to RNA to protein.

Another meaning of the Central Dogma is that all of the information necessary to construct and operate a living organism is contained in its DNA.

We call the complete complement of DNA in a living organism its genome. A genome-sequencing project is the effort to determine the exact sequence of all of the DNA in a particular organism.

The central dogma of biology