Table 5 Correlations between codon bias (Nc′), GC composition, and rates of protein evolution in S. purpuratus
Spearman’s Correlation Coefficient for Each Groupa
Variable 1Variable 2Group 0Group 1Group 2Group 3Group 4All
Codon bias
 Nc′GC3−0.7049***−0.6316***−0.2946***−0.432***−0.4489***−0.7325***
 Nc′GCcds−0.4557***−0.2381***−0.0668***−0.187***−0.1392***−0.5584***
 Nc′GCib0.02790.09190.09330.2226***0.1315*−0.0195
 N′GCf0.1030.06480.1394*0.05470.0917*0.0469
Regional GC composition
 GC3GCcds0.4811***0.3884***0.3299***0.3872***0.2443***0.7409***
 GC3GCi0.08370.1491*0.1259*0.0540.1021*0.2218***
 GC3GCf0.05480.07740.04240.08890.06050.0872*
 GCcdsGCi0.15760.10090.07610.06190.1076*0.2073***
 GCcdsGCf0.09130.03770.00630.09510.0240.0737*
 GCiGCf0.12210.0840.1113*0.11090.1383*0.1333***
Rate comparisonsc
 Nc′dS−0.124−0.1538*−0.0552−0.0243−0.0389−0.1541***
 Nc′dN0.16820.18249*0.05770.1260.1475*0.1571***
 Nc′dN/dS0.22310.2292*0.06670.1330.1515*0.1993***
  • * Significance at P < 0.001. *** Significance at P < 10−10

  • a Number of genes in each group: all (4623), cluster 0 (396), cluster 1 (861), cluster 2 (1154), cluster 3 (912), cluster 4 (1300).

  • b Number of genes with introns for each group: all (4389), cluster 0 (368), cluster 1 (814), cluster 2 (1113), cluster 3 (826), Cluster 4 (1268).

  • c Number of genes with comparative data for each group: all (2954), cluster 0 (225), cluster 1 (593), cluster 2 (744), cluster 3 (563), cluster 4 (829).