The HapMap is also an indicator of human evolution, showing how certain factors developed in particular populations. One variation allows some groups of humans to drink milk beyond infancy, while others are lactose intolerant. The variation could tie in with the domestication of dairy animals.

Results of the first phase of the three-year project were announced Wednesday in the scientific journal Nature. The information is a collection of 1 million genetic bases called single nucleotide polymorphisms, shortened to SNPs.

Completion of the second phase, adding another 2.8 million SNPs, was announced at the press conference. Altogether, humans have about 10 million SNPs.

According to the project Web site, about 99.9 percent of DNA information is common to most people. The remaining 0.1 percent, variants the project is interested in, are crucial. The site says these involve genetic differences that "influence how people differ in their risk of disease or their response to drugs."

By detailing genetic differences in placing the information on the Internet where they are freely available to scientists, the project provides data that can be used to detect genetic disorders and develop therapies.

Collins noted that in April 2003 an international consortium of scientists announced the completion of the mapping of the human genome, the genetic blueprint for a person.

"Today, a different international consortium . . . announces the production of a very different map of the human genome but one that ultimately may prove even more powerful for medical applications," he said.

"The genome project gave us the letters of the DNA code that we all share. But variety is the spice of life. HapMap investigates those spelling differences in the human instruction book that predispose" some people to illness.

We can use the map "to uncover virtually any heritable cause of virtually any common disease." For the past 20 years he has dreamed of using genetic information to diagnose, treat and prevent disease.

"Today's HapMap announcement brings us a major step closer to the realization of that dream," Collins said.

Leavitt expressed warm congratulations. "This is a profound step forward. It is a triumph for collaborative science," he said.

The former governor noted that he used to invite leaders of "medically significant" families to the governor's mansion to talk about joining genetic studies. One man said he was diagnosed with macular degeneration on his 70th birthday, as had his father on his 70th. His grandfather also had learned that he suffered from that form of eye deterioration.

The man told Leavitt he thought there must be something to genetics. He said he has a grandson and wants to help him avoid the problem.