The method by which the sample for the entity was produced.
Entities isolated directly from natural sources (tissues, soil
samples etc.) are expected to have further information in the
ENTITY_SRC_NAT category. Entities isolated from genetically
manipulated sources are expected to have further information in
the ENTITY_SRC_GEN category.
Mandatory Code no
Data Type Code ucode
|| entity isolated from a natural source
|| entity isolated from a genetically
|| entity obtained synthetically