<B><P>Supporting Text</P>
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<B><P>Origin of Replication</B>. <I>Picrophilus torridus</I> contains several long direct and inverted repeats in the range of 100-369 bp (Table 2). Although all long repeats lie in coding regions and have only two copies, 24 short direct repeats with a length of 35-39 bp are found clustered in a noncoding stretch of ~3,000 bp, which at the same time represents the largest noncoding region in the genome. Keto-excess plot and GC skew localize the origin of replication in this area (Figs. 7<SUP> </SUP>and 8) and coding regions for a DNA polymerase and a DNA helicase are found close to its 3' end. Although no inverted repeats can be found and the gene for the cdc6/orc1 homolog is not in close proximity, we assume this region to be the origin of replication in this organism. In the vicinity of the predicted OriR we found many genes unique to <I>P. torridus</I> as well as a high concentration of genes, which so far were only found in <I>Bacteria</I> (Fig. 6).</P>