Subtypes of biomaterial items

[Nicklas Nordborg]

It could be useful to be able to assign subtypes to biomaterials. The use case is that the lab procedure involves several steps at the same biomaterial major type. Eg. sample --> sample --> extract --> extract --> extract --> labeled extract.

For filtering, batch importing, and other gui purposes it would be useful to assign subtypes for each step. The subtypes can be defined by an administrator/power user. Should they be globally readable or use the sharing system for access control?