Table 2

Likelihood ratio tests using various models to determine the selective pressures on the cetacean Hr gene
Models ω(dN/dS) lnLa npb Models compared 2Δ(lnL)c P-values
Dataset I: 17 sequences (16 terrestrial mammals plus the ancestral cetacean sequence)
A. All branches with the same ω ω = 0.27908 −24914.624502 34
B. Branch a (ancestral to cetacean) with ω2, other branches with ω1 ω1 = 0.27502, ω2 = 0.40432 −24912.059374 35 A vs B 5.130256 0.024
C. Branch a with ω2 = 1, other branches with ω1 ω1 = 0.27427, ω2 = 1 −24925.508371 34 B vs C 26.89799 2.14E-07
Dataset II: 19 sequences (16 terrestrial mammals plus two baleen whales and the ancestral sequence of toothed whales)
D. All branches with the same ω ω = 0.28065 −25530.203259 38
E. Branch b (ancestral to toothed whale) with ω2, other branches with ω1 ω1 = 0.27911, ω2 = 0.48639 −25528.780477 39 D vs E 2.845564 0.092
F. Branch b with ω2 = 1, other branches with ω1 ω1 = 0.27890, ω2 = 1 −25530.928574 38 E vs F 4.296194 0.038
Dataset III: 22 sequences (16 terrestrial mammals plus five toothed whales and the ancestral sequence of baleen whales)
G. All branches with the same ω ω = 0.28417 −26239.723434 44
H. Branch c (ancestral to baleen whale) with ω2, other branches with ω1 ω1 = 0.28182, ω2 = 0.62531 −26236.569206 45 H vs G 6.308456 0.012
I. Branch c with ω2 = 1, other branches with ω1 ω1 = 0.28170, ω2 = 1 −26237.557075 44 H vs I 1.975738 0.160

Note: a, ln L is the log-likelihood score; b, number of parameters; c, twice the difference in ln L between the two models compared.

Chen et al.

Chen et al. BMC Evolutionary Biology 2013 13:34   doi:10.1186/1471-2148-13-34

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