Add OMA node IDs in single species complete files
All the single-species complete files could also provide OMA node IDs associated to each gene, in order to be able to find paralogs.
In the case of single-species, I guess this OMA node ID should be the same as the
OMAParentNodeId in the table
gene. In case of a duplication, this OMA node ID should have no taxon ID associated. Verify that these 2 assumptions are correct.