**30**wrote:

Dear member,

I am performing analysis with various models of codeml to detect pattern on evolution on a disease gene set. I am performing the same analysis on 6 and 16 species of mammal, separately. Though in both the cases I am getting my gene sets are evolving under purifying selection. But while performing chi square test, p-value of 6 species (p-value=0.007) is getting significant while that of 16 species in unsignificant (p-value=0.8). Now, I am bit worried, if it is okay to report result of 6 species and i discard 16 species data. or shall i report about 16 species by statiing that these genes are evolving under weak purifying selection

Thanks in advance

**3.2k**• written 4 weeks ago by rprog008 •

**30**

If the p-value is non-significant, it means you can not reject the null hypothesis - for codeml, I believe the null hypothesis is "the sequences are evolving neutrally". So you can't reject the sequences are evolving neutrally, and you can't say these genes are "evolving under weak purifying selection".

Some interesting reads:

Still Not Significant

Misuse of ‘trend’ to describe ‘almost significant’ differences in anaesthesia research

28kThanks a lot for clearing my doubt and for sharing interesting articles. :)

30