FIG. 2.

Phylogenetic tree based on maximum-parsimony analysis of the β-galactosidase gene of isolate SOS Orange and closely related species. Gene sequences from the following organisms were used (the numbers in parentheses are GenBank accession numbers): Bacillus circulans A (AAA22258), Caldicellulosiruptor sp. strain 14B (CAA10365), Bacillus circulans B (AAA22260), Clostridium perfringens (BAA08485), Bacillus stearothermophilus (P19668), Haloferax alicantei (AAB40123), Thermotoga neapolitana (AAC24217), Thermus sp. strain A4 (BAA28362), Thermus sp. strain T2 (CAB07810), Thermus brockianus (AAD33667), Thermotoga maritima 1 (AAD36270), Thermotoga maritima (AAD35398), and Bacillus subtilis (CAB12527).