On 2013 Dec 19, Scott Federhen commented:

I am Scott Federhen, head of the GenBank taxonomy group, and author of his article. Since this article appeared, we have added a significant new feature to the taxonomy database - we have started to curate type material, and are using these data to flag sequence from type in Entrez. Sequence from type material is an important subset because the species identification is virtually certain to be correct (by definition) - but see Buddruhs N, 2013 for a rare cautionary example.

When a new species of prokaryote is described, the authors are required to designate a type strain and deposit it in at least two different culture collections. These are usually widely distributed between other culture collections and sold to researchers, so we have lots of sequence from type strains of prokaryotes, including many of our complete genomes.

When a new species of eukaryote is described, the authors are required to designate a type specimen and deposit it in a museum (or herbarium) where it is generally not available for subsequent sequence analysis (unless living cultures can be derived from the specimen, as with some of the fungi). We currently have very little sequence from type in the plants and animals, though it is becoming more common to include a little sequence with the description of new species - see Stoev P, 2013 for an extreme example.

See Salmonella enterica and Cercopithecus lomamiensis for examples of type material annotation in the taxonomy database.

The Entrez query sequence from type [filter] can be used to retrieve these sequence entries, and can be used in combination with other queries, e.g.: sequence from type [filter] AND metazoa[orgn].

sequence from type [filter] is also a very useful as an Entrez query to limit your BLAST searches to reliably identified sequences (particularly in the prokaryotes).

On 2013 Dec 19, Scott Federhen commented:

I am Scott Federhen, head of the GenBank taxonomy group, and author of his article. Since this article appeared, we have added a significant new feature to the taxonomy database - we have started to curate type material, and are using these data to flag sequence from type in Entrez. Sequence from type material is an important subset because the species identification is virtually certain to be correct (by definition) - but see Buddruhs N, 2013 for a rare cautionary example.

When a new species of prokaryote is described, the authors are required to designate a type strain and deposit it in at least two different culture collections. These are usually widely distributed between other culture collections and sold to researchers, so we have lots of sequence from type strains of prokaryotes, including many of our complete genomes.

When a new species of eukaryote is described, the authors are required to designate a type specimen and deposit it in a museum (or herbarium) where it is generally not available for subsequent sequence analysis (unless living cultures can be derived from the specimen, as with some of the fungi). We currently have very little sequence from type in the plants and animals, though it is becoming more common to include a little sequence with the description of new species - see Stoev P, 2013 for an extreme example.

See Salmonella enterica and Cercopithecus lomamiensis for examples of type material annotation in the taxonomy database.

The Entrez query sequence from type [filter] can be used to retrieve these sequence entries, and can be used in combination with other queries, e.g.: sequence from type [filter] AND metazoa[orgn].

sequence from type [filter] is also a very useful as an Entrez query to limit your BLAST searches to reliably identified sequences (particularly in the prokaryotes).