International Business Machines Corp. said yesterday that it will join a large consortium of drug companies working to compile a map of human genetic diversity as a new way to fight disease.

The company's move symbolizes the growing importance of computers and software in the biological sciences. As the Human Genome Project and various private companies compile vast amounts of information on the genetics and chemistry of living things, powerful computers are becoming essential tools for managing the deluge.

Already, some biotech companies have more computer scientists than biologists on their payroll.

Both to win goodwill and to gain insight on the computer needs of biologists, IBM is becoming a member of the SNP Consortium, an unusual collaboration that was launched by drug companies and academic laboratories.

The firms are paying the labs to develop a preliminary map of SNPs, or single-nucleotide polymorphisms, the one-letter variations in the genetic code that are believed to underlie much of the diversity of the human race. The theory is that researching these one-letter variations may provide important clues to the origin of disease, insight into why drugs affect people differently, and ideas for new drugs.

IBM is the second information-technology company to join the $50 million project. Motorola Inc. had already done so. Ten pharmaceutical companies are members, and another big backer is the Wellcome Trust of Britain, the world's second-largest charity.

For IBM, the new move is part of a broad, aggressive push into the field known as "computational biology." The company has brought one product to market and plans to develop others, encompassing both hardware and software, for biological analysis.

"Some people have said life sciences will be to the first few decades of this century what semiconductors were to the last few decades of the last century," said Dan McCurdy, IBM vice president for life sciences. "I believe that's true."