Site-Specific Mobilization of Vinyl Chloride Respiration Islands by a Mechanism Common in Dehalococcoides

BMC Genomics

Table 1 Divergence Time Estimates Under Different Rates of Evolution.

Divergence of interest	Tree Calculation Method	Divergence time estimates from different proposed rates
		Universal bacterial rate in nature		Empirical E. coli rates in culture		DONNA2/ strain 195 divergence	16S clock
Dehalogenimonas/Dehalococcoides MRCA	Splitstree	5	(1.9/28/33/34)	0.9	(0.4/5.3/6.2/6.3)	0.5	200-600
	ML	3	(1.2/18/21/21)	0.5	(0.2/3.2/3.8/3.9)	0.3
Dehalococcoides MRCA	Splitstree	0.3	(0.14/2/2.4/2.4)	0.06	(0.03/0.37/0.44/0.44)	0.04	30-60
	ML	0.4	(0.17/2.5/3/3)	0.08	(0.03/0.47/0.55/0.56)	0.04
ssrA-GI integration modules MRCA	ML	3	(1.1/16/19/19)	0.5	(0.2/3/3.5/3.6)	0.2
integration modules MRCA, vcr-GIs only	ML	1	(0.4/5.5/6.5/6.6)	0.2	(0.07/1/1.2/1.2)	0.08
vcrAB MRCA	ML	0.05	(0.02/0.27/0.31/0.32)	0.008	(0.03/0.47/0.55/0.56)	0.004
vcrAB, leader masked	ML	0.01	(0.004/0.057/0.067/0.068)	0.002	(0.001/0.010/0.012/0.013)	0.0009

Reported age estimates (left, no parenthesis) are based on the rate of evolution listed in the column header as well as the average Dehalococcoides doubling time from published values (2 days). All estimates are reported in units of 1 million years. Age estimates of the Dehalococcoides clade from the Splitstree consensus network are based on branch lengths of strains to the common network node. '16S clock' is based on 1-2% 16S rRNA gene divergence per 50 million years [83]. Values in parenthesis are results from different doubling time estimates: 0.8 days - the fastest reported doubling time for Dehalococcoides [6]; 11.71 days - anaerobic benthic sediment community doubling time [49]; 13.76 days - bacterial doubling time in anaerobic seawater [48]; 14 days - approximate doubling time of the strictly anaerobic annamox bacteria [47]. For the secondary calculations of age estimates, an extra significant digit has been reported to allow distinguishing of estimates.

ISSN: 1471-2164