BOSTON--Thirty years from now, human cells may be modeled on computers, medicine may be custom-tailored to each person's genes and humanity will be confronted with the possibility of genetically modifying its children because of the nearly completed sequencing of the human genome.

Dr. Francis Collins laid out a roadmap for the future of genetic research in a talk at Harvard Medical School (HMS) last night.

Collins, who is the director of the publicly-organized effort to sequence and analyze the human genome, made his first appearance at Harvard since the publication of his group's landmark paper interpreting the genome in the scientific journal Nature last week.

He spoke to a packed room in the MEC Amphitheater at HMS. The amphitheater filled to capacity 15 minutes before the scheduled start time of the talk and many in the audience were forced to watch on television monitors from other rooms in the building.

Collins, who has been the director of National Genome Research Institute at the National Institutes of Health since 1993, listed the top ten surprises that came out of his group's analysis of the nearly-completely sequenced human genome.

Among the top surprises are the relatively low number of genes predicted to exist, the discovery of many genes borrowed directly from bacteria and a mutation rate much higher in males than in females that makes males more susceptible to genetic diseases but more responsible for human evolutionary processes.

He spoke frankly about what sorts of scientific discoveries he expects will come from the genome, as well as the ethical dilemmas those discoveries will create.

"The genome told us more about biology than anyone imagined," said Collins.

The talk was the first in a series sponsored by the Harvard Health Caucus, a student group based at HMS that sponsors discussion of health policy issues.

Collins emphasized that all humans have 99.9 percent of their genetic codes in common and there is very little variation between human groups from different locations.

"Most of those variations existed when we were all black Africans," he said. "There is no scientific basis for using ethnic or racial categories."

In addition to the discoveries about the differences between humans, Collins said the genome would allow doctors to predict and diagnose disease, as well as develop new drugs more quickly.

"The motivation for this is medical," he said. "We want to understand the hereditary sources of virtually every disease."

Collins said "pharmacogenomics," or the study of how medicines can be tailored to specific people, is already showing promise.

"The idea that we would want the genotype before writing the prescription is not far off," he said.

Collins spoke of the need for legislation to regulate how genetic information can be used. He also stressed that humans are much more than the sum of their genes.

"In all of this excitement about genetics, will we forget that we are much more than is written in our DNA?" he asked. "We shall not learn about the human spirit or what love is by studying the DNA molecule. Scientists sometimes run the risk of feeding into a very mechanical view of biology."

In a question and answer session after the hour-long talk, one audience member asked for Collins' thoughts on genetic research in the private sector, specifically mentioning Celera Genomics, a private company that has been engaged in a much-publicized competition with Collins' project to sequence and interpret the genome.

"Celera has obviously been a very important force to reckon with in the past few years," Collins said. He stressed that the perceived rivalry was not as intense as is has been portrayed.

"This wasn't especially rancorous and it wasn't a race," he said.

According to Matthew W. Fei, a member of the Caucus' four-member steering committee and a second year medical student at HMS, the program is meant to bring people from various Harvard graduate schools to talk about the implications of sequencing the human genome.

"The whole point is to get students from all disciplines to talk to each other," he said.

Fei said he was especially happy that Collins had accepted his group's invitation to speak.

"He's one of the few scientists who is very articulate in expressing complex scientific topics," he said. "We're ecstatic he agreed to come."

Fei expressed approval that Collins took stands about the impact of the genome outside of science.

"I was happy to see is that he wasn't afraid to give his own opinion," he said.

Future events in the Harvard Health Caucus' program, titled "Pandora's Box? The Social Implications of the Human Genome Project" include panel discussions on genetic privacy next week at Harvard Law School and on "Finding God in the Genome" in April at Harvard Divinity School.