A gram of soil can harbor more than 10,000 species of microscopic organisms. Subtle differences in the local environment-say, gases seeping from a petroleum deposit far below-can affect which microbes wind up in a plot of dirt. Mill Valley, CA-based startup Taxon hopes to take advantage of these phenomena to go prospecting for oil and other valuable resources.

Taxon uses DNA sequencing and other techniques to generate for each soil sample a genetic profile-an indication of which species are present and in what proportions. The idea, says chief science officer Matt Ashby, is to analyze soil near known deposits of oil, gold, platinum and other valuable materials to find signature microbial profiles. Then, says Ashby, these signatures could provide the basis for quick handheld testing devices that prospectors could use in the field. Taxon, which was launched last September, is working with the U.S. Department of Energy to develop its first profiles, on soil from an oil field in Wyoming.