metadata is, generically, data about data.  Same in BioC as elsewhere.

So, concretely, let's look at TxDb.Dmelanogaster.UCSC.dm3.ensGene.

The annotations of gene/transcript locations and their IDs are the actual
data. But, if you pull up the TranscriptDb object, there's a lot more
information, too.

R> TxDb.Dmelanogaster.UCSC.dm3.ensGene
TranscriptDb object:
| Db type: TranscriptDb
| Supporting package: GenomicFeatures
| Data source: UCSC
| Genome: dm3
| Genus and Species: Drosophila melanogaster
| UCSC Table: ensGene
| Resource URL: http://genome.ucsc.edu/
| Type of Gene ID: Ensembl gene ID
| Full dataset: yes
| miRBase build ID: NA
| transcript_nrow: 23017
| exon_nrow: 69155
| cds_nrow: 59573
| Db created by: GenomicFeatures package from Bioconductor
| Creation time: 2012-09-10 13:00:23 -0700 (Mon, 10 Sep 2012)
| GenomicFeatures version at creation time: 1.9.39
| RSQLite version at creation time: 0.11.1
| DBSCHEMAVERSION: 1.0

The information about where the transcripts came from (Ensembl), what
organism they are for (Drosophila melanogaster), what genomic assembly this
corresponds to (dm3), when the package was built (9/10/2012), what version
of GenomicFeatures built it... these are all metadata.

Hence, data about the data.  Useful in resolving issues when the data
itself conflicts across sources, assemblies, builds, or simply between lab
groups...



On Tue, Jan 29, 2013 at 1:15 PM, Wang Peter <wng.peter@gmail.com> wrote:

> what i mean is :
>
> generally,
>
>  the metadata == "annotation imformatioin"
>
> in any bioconductor context.
>
>
> > --
> > Steve Lianoglou
> > Graduate Student: Computational Systems Biology
> >  | Memorial Sloan-Kettering Cancer Center
> >  | Weill Medical College of Cornell University
> > Contact Info: http://cbio.mskcc.org/~lianos/contact
>
>
>
> --
> shan gao
> Room 231(Dr.Fei lab)
> Boyce Thompson Institute for Plant Research
> Cornell University
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> Office phone: 1-607-254-1267(day)
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>
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-- 
*A model is a lie that helps you see the truth.*
*
*
Howard Skipper<http://cancerres.aacrjournals.org/content/31/9/1173.full.pdf>

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