But Taylor was among the researchers who doubted so many species had remained viable without the benefits of genetic recombination that sexual reproduction provides. Pursuing this approach with Coccidioides, the researchers found that the genetic material showed evidence of a high degree of recombination that must come from sex. We also found great genetic variation in the genomes, maybe too much for members of the same species. Post-doc Vasso Kaufopanou compared the DNA sequences from different geographic regions and concluded that the Texas and Arizona Valley Fever fungi have been genetically isolated from their California relatives for at least eight million years, long enough for the two groups to become separate species. Such genetic differences offer a potential clinical benefit.
Fungi are notoriously difficult to treat, and new drugs are in high demand.
Now that clinicians understand that fungi from different regions have a different genetic makeup, Taylor says, they can include fungi with different genotypes in their drug and vaccine trials. It's difficult to overstate the power of the newfound ability to retrieve, through genetic analysis, what would otherwise remain unknown and unknowable. Recently, off the southeastern U.S. coast, a research team discovered vast deposits of waxy, methane-containing compounds called clathrates in ocean sediments 500 meters below sea level. Based on unique DNA signatures, archaeal microbes appear to be producing the deposits. The clathrates contain enough hydrocarbons to power the United States for centuries.