Elio Schaechter of Small Things Considered describes the work by members of Jill Banfield’s lab at Berkeley on a unique set of mine-dwelling microorganisms dubbed ARMAN (for Archaeal Richmond Mine Acidophilic Nanoorganisms). These microbes illustrate many surprising characteristics such as "their genomes straddle major evolutionary divides. Phylogenetically, they fit within the Euryarchaeota, yet the majority of their genes that can be assigned to COG’s (clusters of orthologous groups) are of the Crenarchaeota type. Just as surprising, as many as 21% of their genes look like they are bacterial! And some 25-38% of the genes, depending on the strain, have no homologies with anybody else."
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