Researchers predict infinite genomes

ROCKVILLE, Md., Sep 22, 2005 (United Press International via COMTEX) -- Scientists at a Rockville, Md., research center say investigators might never fully describe some bacteria and viruses because their genomes are infinite.

Ever since the genomics revolution started, scientists have been busily deciphering vast numbers of genomes. Public databases now hold 239 complete bacterial genomes.

But scientists at The Institute for Genomic Research, using comparative genomics and mathematics, say as soon as soon as one strain of a species is sequenced, scientists will find significant new genes. Sequence another strain, and they will find more. And so on, infinitely.

"Many scientists study multiple strains of an organism," says TIGR President Claire Fraser. "But at TIGR, we're now going a step further, to actually quantify how many genes are associated with a given species. How many genomes do you need to fully describe a bacterial species?"

TIGR scientists say they've showed unique genes will continue to emerge, even after thousands of genomes are sequenced. The GBS pan-genome is expected to grow by an average of 33 new genes every time a new strain is sequenced.

Their latest research is published in the current early online edition of the Proceedings of the National Academy of Sciences.