Figure 1.

The archaeal gene core: changes resulting from the appearance of new genome sequences. Black bars indicate the current set of pan-archaeal genes (313 COGs); gray indicates COGs that are not part of the current pan-archaeal core but are seen to be conserved after the addition of the given genome sequence. The genomes are listed from left to right in chronological order of release of the complete sequence; species name abbreviations are as in Table 1.