(possible) Update to "source material identifiers" [MIXS:0000026]

[only1chunts]

Current term details

Term name -  source material identifiers
Term ID - MIXS:0000026
Structured comment name - source_mat_id
Definition - A unique identifier assigned to a material sample (as defined by http://rs.tdwg.org/dwc/terms/materialSampleID, and as opposed to a particular digital record of a material sample) used for extracting nucleic acids, and subsequent sequencing. The identifier can refer either to the original material collected or to any derived sub-samples. The INSDC qualifiers /specimen_voucher, /bio_material, or /culture_collection may or may not share the same value as the source_mat_id field. For instance, the /specimen_voucher qualifier and source_mat_id may both contain 'UAM:Herps:14' , referring to both the specimen voucher and sampled tissue with the same identifier. However, the /culture_collection qualifier may refer to a value from an initial culture (e.g. ATCC:11775) while source_mat_id would refer to an identifier from some derived culture from which the nucleic acids were extracted (e.g. xatc123 or ark:/2154/R2). 
Expected value - for cultures of microorganisms: identifiers for two culture collections; for other material a unique arbitrary identifer 
Value syntax - {text}
Example - MPI012345 
Preferred unit - 
Package(s) - 

Suggested update(s) Raised for discussion in v6 review, but not resolved, some notes from the spreadsheet:

refine definition, to clarify that this is the ID of the sample, originally collected;
KEEP for Parent Sample, need another ID space/naming for subsamples, check with INSDC -- keep the alignment of definition with TDWG. -- TDWG. material_sample_id -- How about 'subsample ID' ?? -- in the definition, include recommendation to use a globally unique identifier, and the name of the source, e.g. NEON

Additional context no change made in v6, added discussion for v7