Data collection: Ensembl

Several restrictions have been associated with this data collection. Please read below for more information.

Data aggregation

This restriction is associated to data collections which are an aggregated set of different types of data. For example, they could allow identification of protein, DNA and RNA within the same collection. One should therefore not expect each record within data collections with this restriction to refer to directly comparable entities.

The reason why this restriction is associated with the data collection is:
While Ensembl data is nominally restricted to vertebrate species, it also includes out groups (Dorsophila, Saccharomyces and C. elegans) used in comparative analysis. These species can also be referenced through Ensembl Genomes datasets.

For more information, please refer to: Ensembl overlap

Identifier multiplicity

This restriction is associated with data collections which assign more than one identifier for a given record. This may be due to a revision of the identification scheme used by a data provider, who wishes to continue to allow historical identifiers to remain valid.

The reason why this restriction is associated with the data collection is:
This data collection uses some 'outlier' organisms, to normalise its dataset, which are not intended to be referenced directly in this collection. In addition, those outlier organisms may be referenced using non-standard identifiers. We recommend that human data be accessed using identifiers beginning with 'ENS', and outlier organisms be referenced through the appropriate collection: WormBase (, SGD ( or FlyBase (