#247 nexml export: symbols added to DNA or AA type

[Mark Holder]

See:
http://treebase.org/treebase-web/search/downloadAStudy.html?id=1006&format=nexml

IDs: S1006 S1028 S10727 S11603 S12278 S13528 S1409 S1499 S1814 S672 S761 S888