Abstract
Distribution and diversity of the genes for the enzyme, dissimilatory sulfite reductase (Dsr), which serve as a genetic marker for microbial sulfate reduction, in the Nankai Trough sediment of off central Japan were surveyed. The genetic material, genomic DNA, was extracted from five piston-cored samples with 41 vertical sections, and full-length Dsr gene sequences (ca. 1.9 kb) were PCR amplified for phylogenetic analysis. A total of 382 Dsr gene sequences yielded three Dsr gene groups : Group I, sulfate-reducing Deltaproteobacterial Dsr ; Group II, Nankai Trough novel Dsr ; and, Group III, previously unknown Dsr.
