Gene content profiles of slow, medium and fast growing strains. Enrichment analysis was carried out using criteria III (Table 2). The fast category had 227 (p = 0.09) genes enriched. The medium growth rate category had only 46 (p = 0.56) genes enriched while the slow category had 324 (p = 0.04) genes. Distributions of possible enrichment profiles are shown in Additional file 1: Figure S4.