Group Class
"OTUa"  grpA
"OTUb"  grpA
"OTUc"  grpB
"OTUd"  grpB
"OTUe"  grpB
"OTUf"  grpB
"OTUg"  grpB
"OTUh"  autre
"OTUi"  autre
"OTUj"  autre