Marking another milestone in the push to decode the master blueprint of the human race, Celera Genomics Corp. of Rockville said yesterday that it had finished mapping small pieces of DNA covering more than 80 percent of the human genetic code.

The company is combining its research with data obtained by the publicly funded Human Genome Project, and Celera said the two data sets together now constitute a "rough draft" of the genetic code that probably covers 97 percent of all human genes. The company said it was on track to publish a virtually complete human genetic code, or genome, before the year is out.

"We think this is not only a monumental moment in Celera's history but hopefully in the future of medicine," said J. Craig Venter, the company's president and chief scientific officer.

Investors, reacting to the prospect that decoding the genome could lead to highly profitable new drugs and treatments, sent Celera shares up 29 percent, to $242, yesterday. As recently as Nov. 1 the shares traded for $38.

Figures released yesterday by Celera indicate the company has, in a matter of months, done roughly half as much work as the publicly funded Human Genome Project. The latter project has been under way for well over a decade but only recently began decoding genetic information on an industrial scale.

Researchers associated with the public effort said yesterday that they did not doubt Celera had accomplished what it claims. But they noted that the work depended in part on their data and was built on decades of public investment in gene-research technology. Moreover, they pointed out, Celera's research will not become public until sometime later this year, and is available now only to a handful of big drug companies that have paid millions for early access. The publicly funded research, by contrast, is made public within 24 hours for use by scientists around the world.

"They have accomplished quite a bit here. It's good news for them," said Kathy Hudson, deputy director of the National Human Genome Research Institute, a part of the National Institutes of Health in Bethesda and the main public agency backing gene research. "But the results of their work are accessible only to those limited number of folks who are subscribing to their database. The Human Genome Project continues on target to meet its commitments to the overall biomedical research community."

Yesterday's announcement was testament to the scale of the enterprise that is Celera. The start-up biotechnology company, funded by PE Corp. of Norwalk, Conn., has built the largest gene-analysis laboratory in the world in two buildings just off Montgomery County's main commercial strip. Celera began analyzing the order of chemical units in human genes just after Labor Day and now appears likely to be the first group in the world to publish a relatively complete genome.

The Human Genome Project is expected to produce a high-quality draft this spring but is not due to publish a finished genome until 2002 or 2003.

By no means, however, does Celera's rapid progress indicate that all problems in genetics and biology are about to be solved. The company has compiled a large body of information showing the order of chemical units in fragments of human deoxyribonucleic acid, or DNA. But it has yet to place those fragments in the correct order, a step that will take months longer at a minimum. Even when it's done, scientists will have to labor hard to figure out what parts of the genome are really genes and what parts are just packaging.

The final and most important step will come after the genes have been identified, as scientists try to figure out exactly how they work in the body. As Venter acknowledged yesterday, that step is certain to take decades.