Ah, I know what's happening here.

All data sets have 4 required phenotypic variables (as they're really info about
the set but at the time we didn't know of a way to attach that sort of
meta-information to the whole set).  species, tissue.type, sample.type and
experiment.type.  

2 things:  
- This needs to be documented
- I thought there was code to verify that these existed before loading but I do
not see it now (before loading into the DB that is).

Also, not sure what "this" is in terms of being a new feature, and not sure what
"this" is in terms of 'this isn't available'.