Analysis and comparison of the pan-genomic properties of sixteen well-characterized bacterial genera

BMC Microbiology

Table 2 Results of comparison between protein content similarity and 16S rRNA gene percent identity

Genus	16S range	Shared proteins			Average unique proteins
		Range	Slope	R ²	Range	Slope	R ²
Bacillus	90.4-100%	1741-5204	231	0.83*	248-3000	-176	0.69*
Brucella	99.9-100%	2495-3060	ND^a	ND	154-454	ND^a	ND
Burkholderia	93.8-100%	2861-6337	192	0.26*	337-4554	-394	0.67*
Clostridium	80.3-100%	917-3333	38	0.47*	141-2987	-60	0.36*
Lactobacillus	85.8-100%	720-2348	42	0.49*	235-1595	-46	0.19*
Mycobacterium	91.3-100%	1258-4327	99	0.13*	87-2994	-151	0.47*
Neisseria	98.4-100%	1470-1794	-263	0.19	206-753	305	0.03
Pseudomonas	93.1-100%	2368-5339	68	0.06*	383-2847	-129	0.37*
Rhizobium	98.9-99.9%	3482-4690	178	0.03	1296-2095	12	0.00
Rickettsia	97.2-100%	743-1275	92	0.49*	48-556	51	0.07
Shigella	97.4-99.7%	2781-3481	122	0.13	463-1185	-113	0.11
Staphylococcus	97.4-100%	1674-2653	72	0.41*	49-923	-18	0.02
Streptococcus	92.6-100%	929-1954	46	0.28*	84-1028	-35	0.15*
Vibrio	90.9-99.8%	2345-3879	142	0.81*	396-2167	-21	0.03
Xanthomonas	99.8-100%	2802-3982	ND	ND	201-1653	ND	ND
Yersinia	97.2-100%	2675-3825	347	0.94*	216-1319	-27	0.94*

For each genus, the range of 16S rRNA gene percent identities for all pairs of isolates from that genus is listed. Under the "shared proteins" heading, "range" indicates the range of shared proteins in pairs of isolates from that genus. The "slope" column indicates the slope of the regression line when the number of shared proteins in each pair of isolates is plotted against their 16S rRNA gene percent identities. The "R²" column contains the square of the standard correlation coefficient between these two variables, and indicates the strength of their relationship. The data under the "average unique proteins" heading are analogous to those under the "shared proteins" heading. Isolates sharing ≥ 99.5% identity of the 16S rRNA gene were not used in the calculation of slope or R². Values marked with "ND" were not determined; despite having different species names, all isolates with sequenced genomes within these genera shared ≥ 99.5% identity of the 16S rRNA gene. An asterisk (*) beside an R² value indicates that it is statistically significant with P-value < 0.05.

ISSN: 1471-2180