A clustering with five classes is required to determine the recipient species signature of H.influenzae. The three most populated classes (collecting 94% of the segments) are chosen to calculate the H.influenzae signature. Mean distance to host and cut-off distance is subsequently found equal to 130 and 239, respectively (Table 1) . Similarly to B.subtilis, one cluster (1.5% of H.influenzae genome) is devoted to the 18 rRNA gene copies (Table 1) . A total of 91% of rRNA is labeled atypical and account for 29% of the outliers.