The study of extremophilicphages may reveal new phage families as well as different mechanisms of infection,
propagation and lysis to those found in phages from temperate environments. We describe a novel siphovirus,
GVE3, that infects the thermophileGeobacillusthermoglucosidasius. The genome size is 141298 bp(G+C
29.6%) making it the largest Geobacillusspp infecting phage known.GVE3 appears to be most closely related to
the recently described Bacillus anthracis phage vB_BanS_Tsamsa, rather thanGeobacillus infecting phages
described thus far.Tetranucleotide usage deviation analysis supports this relationship, showing that the GVE3
genome sequence correlates best with B. anthracis and Bacillus cereus genome sequences, rather than
Geobacillusspp genome sequences.