* COVID-19 PubSeq (part 1)

/by Pjotr Prins/

As part of the COVID-19 Biohackathon 2020 we formed a working group
to create a COVID-19 Public Sequence Resource (COVID-19 PubSeq) for
Corona virus sequences. The general idea is to create a repository
that has a low barrier to entry for uploading sequence data using best
practices. I.e., data published with a creative commons 4.0 (CC-4.0)
license with metadata using state-of-the art standards and, perhaps
most importantly, providing standardised workflows that get triggered
on upload, so that results are immediately available in standardised
data formats.

** What does this mean?

This means that when someone uploads a SARS-CoV-2 sequence using one
of our tools (CLI or web-based) they add some metadata which is
expressed in a [[https://github.com/arvados/bh20-seq-resource/blob/master/bh20sequploader/bh20seq-schema.yml][schema]] that looks like

#+begin_src json
- name: hostSchema
  type: record
  fields:
    host_species:
        doc: Host species as defined in NCBITaxon, e.g. http://purl.obolibrary.org/obo/NCBITaxon_9606 for Homo sapiens
        type: string
        jsonldPredicate:
          _id: http://www.ebi.ac.uk/efo/EFO_0000532
          _type: "@id"
          noLinkCheck: true
    host_sex:
        doc: Sex of the host as defined in PATO, expect male () or female ()
        type: string?
        jsonldPredicate:
          _id: http://purl.obolibrary.org/obo/PATO_0000047
          _type: "@id"
          noLinkCheck: true
    host_age:
        doc: Age of the host as number (e.g. 50)
        type: int?
        jsonldPredicate:
          _id: http://purl.obolibrary.org/obo/PATO_0000011
#+end_src

this metadata gets transformed into an RDF database which means
information can easily be fetched related to uploaded sequences.
We'll show an example below where we query a live database.

There is more: when a new sequence gets uploaded COVID-19 PubSeq kicks
in with a number of workflows running in the cloud. These workflows
generate a fresh variation graph (GFA) containing all sequences, an
RDF file containing metadata, and an RDF file containing the variation
graph in triples. Soon we will at multi sequence alignments (MSA) and
more. Anyone can contribute data, tools and workflows to this
initiative!

* Fetch sequence data

The latest run of the pipeline can be viewed [[https://workbench.lugli.arvadosapi.com/collections/lugli-4zz18-z513nlpqm03hpca][here]]. Each of these
generated files can just be downloaded for your own use and sharing!
Data is published under a [[https://creativecommons.org/licenses/by/4.0/][Creative Commons 4.0 attribution license]]
(CC-BY-4.0). This means that, unlike some other 'public' resources,
you can use this data in any way you want, provided the submitter gets
attributed.

If you download the GFA or FASTA sequences you'll find sequences are
named something like
*keep:e17abc8a0269875ed4cfbff5d9897c6c+123/sequence.fasta* which
refers to an internal Arvados Keep representation of the FASTA
sequence.  Keep is content-addressable which means that the value
e17abc8a0269875ed4cfbff5d9897c6c uniquely identifies the file by its
contents. If the contents change, the identifier changes! We use
these identifiers throughout.

* Predicates

Lets look at all the predicates in the dataset by pasting
the following in a SPARQL end point http://sparql.genenetwork.org/sparql/

#+begin_src sql
select distinct ?p
{
   ?o ?p ?s
}
#+end_src

you can ignore the openlink and w3 ones. To reduce results to a named
graph set the default graph to
http://covid-19.genenetwork.org/graph/metadata.ttl in the top input
box. There you can find a predicate for submitter that looks like
http://biohackathon.org/bh20-seq-schema#MainSchema/submitter.

To list all submitters, try

#+begin_src sql
select distinct ?s
{
   ?o <http://biohackathon.org/bh20-seq-schema#MainSchema/submitter> ?s
}
#+end_src

Oh wait, it returns things like nodeID://b76150! That is not helpful,
these are anonymous nodes in the graph. These point to another triple
and by

#+begin_src sql
select distinct ?s
{
   ?o <http://biohackathon.org/bh20-seq-schema#MainSchema/submitter> ?id .
   ?id ?p ?s
}
#+end_src

you get a list of all submitters including "University of Washington,
Seattle, WA 98109, USA".

To lift the full URL out of the query you can use a header like

#+begin_src sql
PREFIX pubseq: <http://biohackathon.org/bh20-seq-schema#MainSchema/>
select distinct ?dataset ?submitter
{
   ?dataset pubseq:submitter ?id .
   ?id ?p ?submitter
}
#+end_src

which reads a bit better. We can also see the datasets. One of them submitted
by University of Washington is
is http://arvados.org/keep:00fede2c6f52b053a14edca01cfa02b7+126/sequence.fasta
(note the ID may have changed so pick one with above query).


* Fetch submitter info and other metadata


#+begin_src sql
select ?p ?s
{
   <http://arvados.org/keep:e17abc8a0269875ed4cfbff5d9897c6c+123/sequence.fasta> ?p ?s
}
#+end_src

which will tell you that original FASTA ID is "MT293175.1". It also
says the submitter is nodeID://b31228.

#+begin_src sql
select distinct ?id ?p ?s
{
   <http://arvados.org/keep:e17abc8a0269875ed4cfbff5d9897c6c+123/sequence.fasta> <http://biohackathon.org/bh20-seq-schema#MainSchema/submitter> ?id .
   ?id ?p ?s
}
#+end_src

Tells you the submitter is "Roychoudhury,P.;Greninger,A.;Jerome,K."
with [[http://purl.obolibrary.org/obo/NCIT_C42781][predicate]] explaining "The individual who is responsible for the
content of a document." Welcome to the power of the semantic web.

To get more information about the relevant sample

#+begin_src sql
select ?sample ?p ?o
{
    <http://arvados.org/keep:e17abc8a0269875ed4cfbff5d9897c6c+123/sequence.fasta> <http://biohackathon.org/bh20-seq-schema#MainSchema/sample> ?sample .
    ?sample ?p ?o
}
#+end_src

we find it originates from Washington state (object
https://www.wikidata.org/wiki/Q1223) , dated "30-Mar-2020". The
sequencing was executed with Illumina and pipeline "custom pipeline
v. 2020-03" which is arguably not that descriptive.

* Fetch all sequences from Washington state

Now we know how to get at the origin we can do it the other way round
and fetch all sequences referring to Washington state

#+begin_src sql

select ?seq ?sample
{
    ?seq <http://biohackathon.org/bh20-seq-schema#MainSchema/sample> ?sample .
    ?sample <http://purl.obolibrary.org/obo/GAZ_00000448> <http://www.wikidata.org/entity/Q1223>
}
#+end_src

which lists 300 sequences originating from Washington state! Which is almost
half of the set coming out of GenBank.

* Acknowledgements

The overall effort was due to magnificent freely donated input by a
great number of people. I particularly want to thank Thomas Liener for
the great effort he made with the ontology group in getting ontology's
and schema sorted! Peter Amstutz and [[https://arvados.org/][Arvados/Curii]] helped build the
on-demand compute and back-ends. Thanks also to Michael Crusoe for
supporting the [[https://www.commonwl.org/][Common Workflow Language]] initiative. And without Erik
Garrison this initiative would not have existed!