Table 5.

Purifying selection within IFNW and IFNA coding regions.

Family	p-Value	dS-dN
IFNA	0.0	3.824
IFNW	0.0	4.013

The significance of purifying selection in the coding regions of IFNW and IFNA subfamilies was verified through a codon based Z-test analyzing the overall average for the subfamilies. The p-value is shown in the second column with p-values less than 0.05 considered significant. The test statistic, the difference between dN and dS, is shown in the third column. The variance of the difference was computed by using the bootstrap method (1000 replicates).