A little-known synthetic molecule that holds great promise for gene therapy, diagnostics, nanotechnology and other applications will be the subject of a public symposium today.

The world's experts on peptide nucleic acids, hybrids of protein and DNA, will be at the Mellon Institute in Oakland for two days of presentations.

"Pittsburgh has the largest contingent of researchers working on this in the world," said organizer Danith Ly of Carnegie Mellon University. "That's why we decided to hold the symposium," which is the first of its kind since scientists in Denmark first made the hybrids 15 years ago.

A peptide nucleic acid, or PNA, is a synthetic mimic of DNA or RNA and binds to the naturally occurring molecules by following the same biochemical rules laid out by James Watson and Francis Crick, who figured out the structure of deoxyribonucleic acid, DNA, on Feb. 28, 1953, in Cambridge, England.

Much of the work with PNA has been done in test tubes, Dr. Ly said.

"One of the major challenges is how to get these things inside the cells," he said. Some progress has been made to resolve that problem, which will be discussed at the seminar.

About 70 people are expected to attend the symposium, which begins at 9: 45 a.m. today and will continue tomorrow.

"Not many people in industry or in medical fields know about [PNA]," Dr. Ly said. "The whole idea behind the symposium is to bring researchers from academia and industry to discuss the potential use of PNA."