Hello everyone,

I used codon based z test of selection to check selection pressure on a protein and i performed neutral test, positive test, and purifying test. Results of three different tests gave probability and static values which conflict with each other. I want to understand how to interpret results either statistically or biologically??

                           p                 statistic
Neutral test               0.348              -0.942
Positive test              1                  -0.979
Purifying test             0.161              -0.996

significance level = 0.05

Biologically i interpret that dn-ds (statistic) value is negative that means more synonyms changes so negative selection pressure. But if i look statistically every test has greater p value than 0.05 and z value is also in acceptance region for every test so on that basis every test hypothesis is accepted. that is very confusing. Please guide me if I am going in the right direction.