Functional annotation of OrthoMCL groups?
 

One of the cons of OrthoMCL is "OrthoMCL groups do not have function annotations". Could someone suggest me how to annotate the OrthoMCL groups?

You an assign the GO annotation, InterPro matches or Pfam domains to each gene. After this you can find the most overlapping annotation for each group to get an idea for the function of the whole group.