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Data Stewardship (including Archiving) No comments yet

Data Stewardship -
The Conducting, Supervising, and Management of Data

Next-gen sequencing promises to unload reams and reams of data on the world.  Pieces of that data will prove relevant to one or the other of specific research projects in your enterprise.  At the same time, your lab may produce more data by annotation or simple research.  How do you handle it all?

First, you should appoint a data steward.  This person must understand where the data comes from, how it is modeled, who uses what parts of it, and any results this data may produce, such as forms, etc. Most importantly, they must be able to verify the integrity of that data.

Data, Data, Data

I’ve handled lots of engineering and bioinformatics data in my time…

In engineering, I had to be sure all instrumentation was calibrated correctly and production data was representative or correct.  Every morning at 7 a.m., I held a meeting with data analysts, system administrators, database representatives, etc. focused on who was doing what to which data, what data could be archived, what data should be recovered from archive, and so on.   This data inventory session proved to be extremely useful as there were terabytes of data swept through the system on a weekly basis.

For bioinformatics, I had to locate and merge data from disparate sources into one whole and run that result against several analysis programs to isolate the relevant data.  That data was then uploaded to a local database for access by various applications.  As the amount of available sequence data grew, culling the data, storage of this data, and archiving of the initial and final data became something of a headache.

My biggest bioinformatics problem was NCBI data, as that was how we got most of our data.
I spent weeks/months/years plowing though the NCBI toolkit, mostly in debug. Grep became my friend. 

I tried downloading complete GenBank reports from the NCBI ftp website but that took too much space.  I used keywords with the Entrez eutils, but the granularity wasn’t fine enough, and I ended up with way too much data.  Finally, I resorted to the NCBI Toolkit on NCBI ASN.1 binary files.
LARTS would have made this part so much easier. 

The Data Steward should also be familiar with data maintenance and storage strategies.

Our guest blogger, Bill Eaton, explains the difference between backup and archiving of data, and lists the pros and cons of various storage technologies.

Bill Eaton: Data Backup and Archival Storage

  Backups are usually kept for a year or so, then the storage media is reused.
  Archives are kept forever.  Retrievals are usually infrequent for both.

Storage Technologies

Tape:  suitable for backup, not as good for archiving.

Pro: Current tape cartridge capacities are around 800 GB uncompressed.

Cost per bit is roughly the same as for hard disks.

Con: Tape hardware compression is ineffective on already-compressed data.
      Tapes and tape drives wear out with use.
      Software is usually required to retrieve tape contents. (tar, cpio, etc)
      Tape technology changes frequently, formats have a short life.

Optical:  better for archiving than backup

Pro:  DVD 8.5 GB, Blu-Ray  50 GB
      DVD contents can be a mountable file system, so that no special software is needed for retrieval.
      Unlimited reading, no media wear.
      Old formats are readable in new drives.
Con:  Limited number of write cycles.

Hard Disks:  could replace tape

Pro:   Simple:  Use removable hard disks as backup/archive devices.
        Disk interfaces are usually supported for several years.
Con: Drives may need to be spun up every few months and contents
          rewritten every few years.

MAID:  Massive Array of Idle Disks
        Disk array in which most disks are powered down when
        not in active use.

Pro: The array controller manages disk health,
        spinning up and copying disks as needed.
        The array usually appears as a file system. Some can emulate a tape drive.

Con: Expensive.

Classical:  the longest-life archival formats are those known
      to archaeologists. 

Pro:  Symbols carved into a granite slab are
      often still readable after thousands of years.
Con: Backing up large amounts of data this way could take hundreds of years.


ASN.1 to XML: The Process No comments yet


Jim Ostell, speaking at the observance of the 25th anniversary of NCBI, stated something along the lines of, “then they wanted XML, but nah..”.

While working on the filters for the LARTS product, most specifically, the GenBank-like report, I realized how tightly-coupled the NCBI ASN.1/XML is to the toolkit. 

Basically, you’ve got to understand the toolkit code in order to translate what the XML is saying. The infinite extendability and recursive structure of the ASN.1 data model is another conundrum. This is especially true of the of the ASN.1 data structures supporting GenBank data - Bioseq-set. For example, a phy-set (phylogeny set) can include sets of Bioseq-sets nested to several levels. Most Bioseq-sets are the usual nuc-prot (DNA and translating protein), but others are pop-sets, eco-sets, segmented sequences with sets of sequence parts, etc.

After we developed LARTS, I wrote the GB filter as a Java object.  It was an interesting experience. 

NCBI ASN.1 rendered as XML, either our version or the NCBI asn2xml version, is very dependent on  the NCBI toolkit code for proper interpretation.  

The two most glaring examples are listed below.

Sequence Locations

Determing the location of sequence features for a GenBank data report, is a prime example.  Here are a few simple examples:

primer_bind   order(complement(1..19), 332..350)
gene                complement(join(1560..2030, 3304..3321))
CDS               complement(join(3492..3593, 3941..4104, 4203..4364, 4457..4553, 4655..4792))
rRNA  join(<1..156, 445..478, 1199..>1559) 5231, 76582..76767, 77517..77720, 78409..78490))
primer_bind   order(complement(1..19), 1106..1124)

For Segmented-sequences:
CDS         join(162922:124..144; 162923: 647..889, 1298..1570)

CD regions locations have frames, bonds have points (that can be packed), strand minus denotes a complement (reverse order), a set of sequence locations for a sequence feature (packed-seqint) denotes a join, and locations can be “order(”ed, or “one-of”, and fuzz-from and fuzz-to has to taken into account for points and sequence intervals.

Sequence Format

DNA sequences are stored in a packed 2-bit or 4-bit per letter format (ncbi2na and ncbi4na).  2na is used if the sequence does not contain ambiguity, otherwise 4na is the format of choice. The sequence must be unpacked to be useful. This takes a basic understanding of Hex(adecimal).

The NCBI Toolkit contains all of the code necessary to render a GenBank report from the ASN.1 binary or ASCII data file.  (The code is there, but you have to figure out how to compile it into an executable.)

We took the toolkit code and converted  it to Java to produce the GenBank-style output format.  It differs from the actual NCBI GenBank Report in that the LARTS report lists a FASTA-formatted sequence instead of the 10-base pairs per column that the NCBI GenBank Report produces.

The Many Variations of LARTS is provided as an example with Stand-Alone LARTS.  The LARTS Reader enables the GenBank-style report.

Using LARTS Online, the user can select the GenBank-style report as the desired Output Format.

A third option, would entail using LARTS Online to obtain the keyword or keyword/element-path data wanted in XML format. This data is then downloaded to a local machine via the Thick Client option. Finally, Stand-Alone LARTS would process the dowloaded XML data into a GenBank-style report.

Stand-Alone LARTS provides example filters and SQL for processing XML and loading the relevant data into a local SQL database.  This includes sample code for  the BLOB and CLOB objects.

The filter for FASTA-formatting sequence data is also available as an example with Stand-Alone LARTS.

These options provide ready access to NCBI data for your research.

Interpreting Standards No comments yet

I found an article in the December 2008 issue of Nature Methods to be of particular interest, not in the least that I personally know the authors.

The article, under CORRESPONDENCE on page 991, surveyed a series of papers  from the 2007 issues of 20 journals. The purpose was to refute the Nature Methods editorial of March 2008 which asserted that the deposition of supporting raw microarray datasets is “routine”.  Data cited in the article was compared to that currently available in public databases.  They found that the rate of deposition of datasets was less than 50%. Only half of the discovery data that was the basis of the articles was available to the public.

They further cited that the fault of the MIAME (Minimum Information about a Microarray Experiment) standard. They assert that “owing to their highly contextual nature, have a more complex metadata structure than sequence data.”

The MIAME standard was forged by the MGED (Microarray and Gene Expression Data) and published in Nature Genetics, 29, 365-371 (2001).  The MGED also house the the Microarray and Expression (MAGE) Object Model which defines the entire environment of the experiment (e.g. organism, array design, etc.). MIAME is the standard and MAGE adheres to the MIAME standard and suggests formats for representation and submission of microarray data.

The premier microarray data repository is ArrayExpress located at

ArrayExpress is a public repository for transcriptomics data, which is aimed at storing  and MINSEQE for high-throughput data ( - is compliant data in accordance with MGED ( The ArrayExpress Warehouse stores gene-indexed expression profiles from a curated subset of experiments in the repository.

Other sites are GEO (Gene Expression Omnibus - and CIBIX (Center for Information Biology gene Expression database -

MIAMExpress (a MIAME compliant microarray data submission tool) is currently available at and is the submission tool for microarray experiments. It is downloaded to your local system and must be made executable (compiled) on your system in order to use it.  A local of the MySQL database is required as well as the Perl programming language. 

The MIAME/MAGE meta-data model is described in UML (Universal Modelling Language).
They suggest mark-up languages for data submissions. They provide MAGE-ML which is XML dtd.  In addition, there is a tabular format (MAGE-TAB) that has just been announced. It is a spreadsheet-like tabular format.

This data model is difficult to interpret. Fitting your data to this model can be a real trick.  I know, I’ve tried. And I’ve got years of work with formal data specifications behind me.  For the average lab tech it is almost impossible to interpret.  A bioinformatics programmer with exposure to MS Word and MS Excel (which I have read are the two most important requirements to succeed in bioinformatics (!)) would be in the same boat. 

I have nothing against models and standards.  Standards bring order to chaos — if they are simple enough to interpret and implement.

The article goes on to call for the interpretation of the microarray data in the GenBank format.

Just about every everybody in the biosciences field is familiar with this format.  Most important, they know how to submit data that will be interpreted as GenBank data.

GenBank data is stored internally at NCBI in ASN.1.  The ASN.1 format is extensively used in telecommunications and other areas.  After years of working with ASN.1 and especially NCBI ASN.1, I have to say that it is ideal for the storage of sequence and other data.

ASN.1 is infinitely extensible through its recursive abilities.   This is great in that it can encompass all the data for a particular data object.  However, the nesting nature of the ASN.1 construct can cause one to literally pull out one’s hair. 

ASN.1 doesn’t gracefully translate into SQL.  It is possible, but not very pretty and the queries are ridiculously complex. �

Using NCBI toolkit code to access ASN.1 data works if one knows C/C++ and has lots of experience working with suites of large complex software.

Our product (LARTS) was developed to make working with NCBI ASN.1 data a little easier and to create a new paradigm of searching NCBI ASN.1 data.

NCBI ASN.1 was distilled into a grammar that is parsed much like a programming language or the way a sentence is parsed for English class.  That grammar translates the ASN.1 into XML Schema.  This XML can then filtered for specific values or formatted for specific output such as a Genbank-like report.

The new paradigm means that the serious user should become somewhat familiar with the NCBI ASN.1 data structures.  By serious, I mean someone who wants to go beyand the currently offered output formats.

Our ncbixref link ( provides a way to traverse these structures, starting with the top-level Bioseq-set.

In some instances, the ASN.1 data structure names don’t really describe the data they define.  For example, the ASN.1 data structure for dbSNP is ExchangeSet (

Yet Another Standard

The Genomics Standards Consortium has a suggested format for next-generation sequencing experiments called MIGS (, or miminum information about a genome sequence. It’s extension is MIMS - Minimum Information about a Metagenomic Sequence.  The MIGS/MIMS data models are expressed in GCDML — Genomic Contextual Data Markup Language - GCDML is implemented using XML Schema.

Let’s hope the meta-data is kept to that “minimum”, but looking at, it doesn’t seem so.

At any rate, the move toward XML Schema is a good thing and fits in well with our thinking.

HSEMB Conference and GenBank Release 168.0 No comments yet

Events of particular note this week – 

The HSEMB Conference –

The 26th Annual Houston Conference on Biomedical
Engineering Research ( on 19-20 March 2009 at the University of Houston Hilton Hotel and Convention Center.

HSEMB has established the John Halter Award for Professional Achievement in Bioinformatics and Computational Biology.   The late Dr. John Halter is the founder of LifeFormulae, LLC. is the link to our memorial to John.

Super Computing 2008

SC08 - Super Computing 2008, the International Conference for High
Performance Computing, Networking, Storage and Analysis. November
15-21, Austin Convention Center, Austin, Texas.

And GenBank Release 168.0. –

Genbank Release 168.- flat files require roughtly 3871 GB for the sequence files only or 396 GB if you include the ’short directory’, ‘index’ and the *.txt files.  The ASN.1 data files require approximately 338 GB.

Recent statistics for non-WGS (Whole Genome Sequence), non-CON (Contig)  sequences are given below.

  Release  Date       Base Pairs   Entries

  167      Aug 2008   95033791652  92748599
  168      Oct 2008   97381682336  96400790

Recent statistics for WGS sequences:

  Release  Date       Base Pairs   Entries

  167      Aug 2008  118593509342  40214247
  168      Oct 2008  136085973423  46108952

During the 69 days between the close dates for GenBank Releases 167.0
and 168.0, the non-WGS/non-CON portion of GenBank grew by 2,347,890,684 basepairs and by 3,652,191 sequence records.

During that same period,1,111,311 records were updated. An average of about 69,036 non-WGS/non-CON records were added and/or updated per day.

Between releases 167.0 and 168.0, the WGS component of GenBank grew by 17,492,464,081 basepairs and by 5,894,705 records.

The combined WGS/non-WGS single-release increase of 19.84 Gbp for
Release 168.0 is the largest that GenBank has experienced, to date.

That’s a lot data. It’s a long, long way from the set of CDs that came out 4 times a year back in the late 90’s. Somewhere there are drawers and drawers of old Entrez CDs!  (Entrez is the engine used to search NCBI Life Sciences data.)

GenBank is considered an archive of information about sequences.  The nine-digit GI number, once the unique sequence identifier, have been supplanted by the Accession Number.

Speaking of NCBI data, we now have the complete set of the human (Homo Sapiens) data from NCBI’s dbSNP available through our LARTS product.  Currently, the files are not searchable by keyword, or keyword/element path.  This capability should be available to you the early part of next week.

Which brings me to the question.  Is GenBank data as important today as it was, say, 5 years ago?  If not GenBank, what NCBI data is considered critical to your current research and bioinformatics methods, and, if I might also ask, what are you doing with it?

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