Package: biocommons.seqrepo
biocommons.seqrepoSeqRepo is a Python package for storing and reading a local collection of
biological sequences. The repository is non-redundant, compressed, and
journalled, making it efficient to store and transfer multiple snapshots.IntroductionSpecific, named biological sequences provide the reference and coordinate
system for communicating variation and consequential phenotypic changes.
Several databases of sequences exist, with significant overlap, all using
distinct names. Furthermore, these systems are often difficult to install
locally.SeqRepo provides an efficient, non-redundant and indexed storage system for
biological sequences. Clients refer to sequences and metadata using familiar
identifiers, such as NM_000551.3 or GRCh38:1, or any of several hash-based
identifiers. The interface supports fast slicing of arbitrary regions of large
sequences.A "fully-qualified" identifier includes a namespace to disambiguate accessions
from different origins or sequence sets (e.g., "1" in GRCh37 and GRCh38). If the
namespace is provided, seqrepo uses it as-is; if the namespace is not provided
and the unqualified identifier refers to a unique sequence, it is returned;
otherwise, the use of ambiguous identifiers raise an error.SeqRepo favors namespaces fromidentifiers.orgwhenever available. Examples includerefseqandensembl.seqrepo-rest-serviceprovides a REST interface
and docker image.Released under the Apache License, 2.0.|||ChangeLogCitationHart RK, Prlić A (2020).SeqRepo: A system for managing local collections of
biological sequences.PLoS ONE 15(12): e0239883.https://doi.org/10.1371/journal.pone.0239883FeaturesTimestamped, read-only snapshots.Space-efficient storage of sequences within a single snapshot and across snapshots.Bandwidth-efficient transfer incremental updates.Fast fetching of sequence slices on chromosome-scale sequences.Precomputed digests that may be used as sequence aliases.Mappings of external aliases (i.e., accessions or identifiers likeNM_013305.4) to sequences.Deployments ScenariosLocal read-only archive, mirrored from public site, accessed via Python API
(seeMirroring documentation)Local read-write archive, maintained with command line utility and/or API (seeCommand Line Interface documentation).Docker data-only container that may be linked to application container.SeqRepo and refget REST API for local or remote access (seeseqrepo-rest-service)Technical Quick PeekWithin a single snapshot, sequences are storednon-redundantlyandcompressedin an add-only journalled filesystem structure. A truncated SHA-512
hash is used to assess uniquness and as an internal id. (The digest is truncated
for space efficiency.)Sequences are compressed using the Block GZipped Format
(BGZF)), which enables pysam
to provide fast random access to compressed sequences. (Variable compression
typically makes random access impossible.)Sequence files are immutable, thereby enabling the use of hardlinks across
snapshots and eliminating redundant transfers (e.g., withrsync).Each sequence id is associated with a namespaced alias in a sqlite database.
Such as<seguid,rvvuhY0FxFLNwf10FXFIrSQ7AvQ>,<NCBI,NP_004009.1>,<gi,5032303>,<ensembl-75ENSP00000354464>,<ensembl-85,ENSP00000354464.4>.
The sqlite database is mutable across releases.For calibration, recent releases that include 3 human genome assemblies
(including patches), and full RefSeq sets (NM, NR, NP, NT, XM, and XP) consumes
approximately 8GB. The minimum marginal size for additional snapshots is
approximately 2GB (for the sqlite database, which is not hardlinked).For more information, seedocs/design.rst.RequirementsReading a sequence repository requires several Python packages, all of which are
available from pypi. Installation should be as simple aspip install biocommons.seqrepo.Writingsequence files also requiresbgzip, which provided in thehtslibrepo. Ubuntu users should install
thetabixpackage withsudo apt install tabix.Development and deployments are on Ubuntu. Other systems may work but are not
tested. Patches to get other systems working would be welcomed.Quick StartOS X$ brew install python libpqUbuntu$ sudo apt install -y python3-dev gcc zlib1g-dev tabixAll platforms$ python -m venv venv
$ source venv/bin/activate
$ pip install seqrepo
$ sudo mkdir -p /usr/local/share/seqrepo
$ sudo chown $USER /usr/local/share/seqrepo
$ seqrepo pull -i 2018-11-26 
$ seqrepo show-status -i 2018-11-26 
seqrepo 0.2.3.post3.dev8+nb8298bd62283
root directory: /usr/local/share/seqrepo/2018-11-26, 7.9 GB
backends: fastadir (schema 1), seqaliasdb (schema 1) 
sequences: 773587 sequences, 93051609959 residues, 192 files
aliases: 5579572 aliases, 5480085 current, 26 namespaces, 773587 sequences

# Simple Pythonic interface to sequences
>> from biocommons.seqrepo import SeqRepo
>> sr = SeqRepo("/usr/local/share/seqrepo/latest")
>> sr["NC_000001.11"][780000:780020]
'TGGTGGCACGCGCTTGTAGT'

# Or, use the seqrepo shell for even easier access
$ seqrepo start-shell -i 2018-11-26
In [1]: sr["NC_000001.11"][780000:780020]
Out[1]: 'TGGTGGCACGCGCTTGTAGT'

# N.B. The following output is edited for simplicity
$ seqrepo export -i 2018-11-26 | head -n100
>SHA1:9a2acba3dd7603f... SEGUID:mirLo912A/MppLuS1cUyFMduLUQ Ensembl-85:GENSCAN00000003538 ...
MDSPLREDDSQTCARLWEAEVKRHSLEGLTVFGTAVQIHNVQRRAIRAKGTQEAQAELLCRGPRLLDRFLEDACILKEGRGTDTGQHCRGDARISSHLEA
SGTHIQLLALFLVSSSDTPPSLLRFCHALEHDIRYNSSFDSYYPLSPHSRHNDDLQTPSSHLGYIITVPDPTLPLTFASLYLGMAPCTSMGSSSMGIFQS
QRIHAFMKGKNKWDEYEGRKESWKIRSNSQTGEPTF
>SHA1:ca996b263102b1... SEGUID:yplrJjECsVqQufeYy0HkDD16z58 NCBI:XR_001733142.1 gi:1034683989
TTTACGTCTTTCTGGGAATTTATACTGGAAGTATACTTACCTCTGTGCAAAATTGCAAATATATAAGGTAATTCATTCCAGCATTGCTTATATTAGGTTG
AACTATGTAACATTGACATTGATGTGAATCAAAAATGGTTGAAGGCTGGCAGTTTCATATGATTCAGCCTATAATAGCAAAAGATTGAAAAAATCCATTA
ATACAGTGTGGTTCAAAAAAATTTGTTGTATCAAGGTAAAATAATAGCCTGAATATAATTAAGATAGTCTGTGTATACATCGATGAAAACATTGCCAATASeeInstallationandMirroringfor more information.Environment VariablesSEQREPO_LRU_CACHE_MAXSIZE sets the lru_cache maxsize for the sqlite query
response caching. It defaults to 1 million but can also be set to "none" to be
unlimited.SEQREPO_FD_CACHE_MAXSIZE sets the lru_cache size for file handler caching during
FASTA sequence retrievals. It defaults to 0 to disable any caching, but can be
set to a specific value or "none" to be unlimited. Using a moderate value (>10)
will greatly increase performance of sequence retrieval.DevelopingDeveloping on OS Xbrew install python libpq bashIf you get "xcrun: error: invalid active developer path", you need to install
XCode. See thisStackOverflow answer.Developing on Ubuntusudo apt install -y python3-dev gcc zlib1g-dev tabixHere's how to get started developing:make devready
source venv/bin/activate
seqrepo --versionBuilding a docker imageDocker images are available athttps://hub.docker.com/r/biocommons/seqrepo.
Tags correspond to the version of data, not the version of seqrepo, because the
intent is to make it easy to depend on a local version of seqrepofiles.  Each
docker image is an installation of seqrepo that downloads the corresponding
version of seqrepo data.  When used in conjunction with docker volumes for
persistence, this provides an easy way to incorporate seqrepo data into a docker
stack.Buildingcd misc/docker
make 2021-01-29.log  # builds and pushes to hub.docker.com (i.e., you need creds)