Does anyone know if it is possible to specify which assembly to use when constructing a query for Entrez ?

For example, if I do such a query with EDirect:

    esearch -db gene -query "brca1 [ALL]human[ORGN]" -sort "relevance" | \
    efetch -format docsum | \
    xtract -pattern DocumentSummary -element Name MapLocation Description OtherAliases Id \
      -block GenomicInfo -element ChrLoc ChrAccVer ChrStart ChrStop

the GenomicInfo that I get seems to be according to the GRCh38 assembly. The application that I'm developing needs to use the GRCh37 assembly, however.

Any help is much appreciated.
Actually, it turns out that this can be done. I wrote to NCBI and got a response.

The key is to look in the **LocationHistType** block for:

- a specific annotation release (see <a href="http://www.ncbi.nlm.nih.gov/genome/guide/human/release_notes.html" target="_blank">here</a> and <a href="http://www.ncbi.nlm.nih.gov/news/08-27-2013-human-annotation-105/" target="_blank">here</a> for some explanation of annotation releases). For example, GRCh37.p13 is coded by NCBI as Annotation Release *105*.

- the corresponding assembly accession, which is a RefSeq Assembly ID. For GRCh37.p13 it is *GCF_000001405.25* (see <a href="http://www.ncbi.nlm.nih.gov/assembly/GCF_000001405.25/" target="_blank">here</a> for more information). 

The EDirect commands should look something like this:

       esearch -db gene -query "brca1 [ALL] AND human [ORGN]" | \
       efetch -format docsum | \
       xtract -pattern DocumentSummary \
         -element Name MapLocation Description OtherAliases Id ChrLoc \
         -block LocationHistType \
           -match "AnnotationRelease:105" -and "AssemblyAccVer:GCF_000001405.25" \
             -element ChrAccVer ChrStart ChrStop