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.
|man|| entity isolated from a genetically
|nat||entity isolated from a natural source|
|syn||entity obtained synthetically|