Table 6 Correlations between gene size and mRNA expression, codon bias (Nc′), and GC content in S. purpuratus
Spearman’s Correlation Coefficient for Each Groupa
Variable 1Variable 2Group 0Group 1Group 2Group 3Group 4All
Coding and transcript lengths
 NcodonsmRNA levelb−0.2305*−0.1052−0.1366*−0.0823−0.0605−0.1164***
 NcodonsNc′0.1991*0.2118*0.05590.2119*0.1226*0.0649*
 NcodonsGCcds−0.1058−0.1738*0.1404*0.0106−0.05580.0345
 NexonsmRNA level−0.1316−0.0437−0.0346−0.0578−0.0315−0.0507*
 TlengthmRNA level−0.1379−0.0521−0.0128−0.0354−0.0233−0.0574*
 TlengthNc′0.1055−0.0697−0.0915−0.112*−0.0412−0.049*
  • mRNA, messenger RNA. *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 log10(maximum observed expression in AU).