Table 3

Ratio ds/dn for the nucleotide substitutions found in the bacteriophage Qβ populations evolved in the presence of AZC
Repeated mutations counted once Repeated mutations counted all the times they appear
Population Non polymorphic substitutions2 Polymorphic substitutions2 Non polymorphic Substitutions2 Polymorphic Substitutions2
Qβ-AZC(t60) 5.7 4.0 5.3 1.7
Qβ-AZC(t70) 5.7 2.7 6.9 1.5
Qβ-AZC(t90) 7.2 3.2 7.1 1.6
Average3 6.2 ± 0.9 3.3 ± 0.7 6.4 ± 1.0 1.6 ± 0.1

1The value ds/dn indicates the ratio of synonymous to non synonymous substitutions corrected by the potential number of synonymous and non synonymous positions. The genomic region analyzed comprised from nucleotide 1485 to nucleotide 4028, excluding the non coding region (from nt 2331 to nt 2351). The number of synonymous and non synonymous positions was evaluated using the program SNAP [34,35].

2Polymorphic substitutions (those shown in Table  1 together with the fixed substitutions A1746U and A2187C) and non polymorphic substitutions (those shown in Additional file 1) were analyzed separately. All these mutations were placed in coding regions.

3Average value of the ratio ds/dn for the 3 populations analyzed. The difference between the average values obtained for non polymorphic and polymorphic substitutions was significant (p < 0.01 in both analysis, Student’s t test for the difference of means).

Cabanillas et al.

Cabanillas et al. BMC Evolutionary Biology 2013 13:11   doi:10.1186/1471-2148-13-11

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