Many scientists study multiple strains of an organism, says The Institute for Genomic Research (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.”
TIGR scientist Hervé Tettelin and colleagues have published a study in the early online edition of the Proceedings of the National Academy of Sciences.
TIGR scientists, with collaborators compared the genomic sequence of eight isolates of the same bacterial species: Streptococcus agalactiae, also known as Group B Strep (GBS).
Analysing the GBS genomes, the researchers discovered a surprisingly continual stream of diversity. Each GBS strain contained an average of 1806 genes present in every strain (thus constituting the GBS core genome) plus 439 genes absent in one or more strains. Moreover, mathematical modelling showed that unique genes will continue to emerge, even after thousands of genomes are sequenced.
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