. 2011 Nov 4;3:1369–1380. doi: 10.1093/gbe/evr115

Table 4.

Selective Constraint Estimated with Three Models of Gene Evolution for Ion Transporters of A. thaliana, C. papaya, and P. trichocarpa

		PHT1–High-Affinity Phosphate Transporter		PHT2–Low-Affinity Phosphate Transporter		PHT3-Mitochondrial Phosphate Transporter		PHT4-Chloroplast Phosphate Transporter		NHX-Sodium Ion Transporter
Model	Branches	K_a/K_s	−lnL	K_a/K_s	−lnL	K_a/K_s	−lnL	K_a/K_s	−lnL	K_a/K_s	−lnL
R_Null	All	0.076		0.207		0.114		0.148		0.049
			15379.5		3577.0		5898.3		24869.3		11210.1
R_Dupl	Speciation	0.063^a		0.156^a		0.080^a		0.123^a		0.062^a
R_Dupl	Duplication	0.082^a		0.415^a		0.133^a		0.249^a		0.031^a
			15376.7		3570.2		5894.1		24847.0		11188.5
R_WGD	Speciation	0.063		—^b		0.080^a		0.123		0.061^a
	WGD^c	0.081		—		0.190^a		0.233		0.067^a
	SSD^d	0.085		—		0.112^a		0.265		0.018^a
			15376.6		—		5891.2		24846.7		11175.3

Bold values indicate a significant improvement over the model immediately above at P < 0.05; nested likelihood ratio test (distributed χ², P < 0.05, degrees of freedom = 1).

No small scale duplications in PHT2, so model R_Dupl is equivalent to model R_WGD.

WGD: determined by syntenic paralogy using the Plant Genome Duplication Database (Tang, Bowers, et al. 2008).

SSD: determined either by a lack of syntenic paralogy and/or by tandem duplication status.