Applications of Darwin's Theory

From the SF Chronicle:

...as scientists mark Darwin's 200th birthday this month, evolution is no longer simply a narrative of life. Scientists have begun using it as a tool to develop new technologies.

By doing so, they have improved law enforcement, created smarter computer programs and are remaking the field of medicine. There have been quirkier applications, such as cleaner clothes, too.

Only recently, though, have scientists begun calling attention to these breakthroughs, as the ideas of the iconic English naturalist have faced renewed attacks.

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One of the first and most well-known uses of evolutionary theory has come in law enforcement.

Among the 3 billion or so chemical bits, or letters, in human DNA are those that change slowly and those that mutate rapidly. Scientists realized that short segments of DNA vary greatly from person to person as a result. The finding gave rise to the concept of DNA fingerprints to identify individuals.

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Evolution also has helped scientists become smarter about the development and use of medicines such as antibiotics and vaccines.

Physicians now understand that bacteria mutate over time. When attacked by antibiotics, some bacteria become resistant to certain antibiotics and thrive.

"Evolutionary theory has definitely guided us, and now we as a medical community know to be much more careful about the use of antibiotics," said Dr. James Versalovic, a Baylor College of Medicine professor and the director of microbiology at Texas Children's Hospital.

The evolution of viruses also is critical to the development of vaccines. Some viruses, such as polio, have genetic material that changes slowly over time, allowing physicians to create a vaccine that will last for life.

Other viruses, including influenza and HIV, are constantly changing. This requires annual changes to the flu vaccine and has prevented development of a successful vaccine against HIV.

"We know we are in a world where we are in a constant competition with bacteria and viruses," said Dan Graur, a University of Houston biologist. "We need to use evolutionary principles just to keep them under control."

Some scientists also use evolution to develop drugs to combat disease, an approach called "directed evolution."

Biologists employing this method generate a large batch of random segments of DNA- short strips of biological material - which are then tested to see whether any will perform a useful function inside cells, such as binding to a protein. The DNA segments that fail at the task are eliminated; those that succeed are copied in such a way that new mutations are introduced. These new variants then are tested. The process is replicated many times until an optimal sequence is found.