[Bioc-devel] custom genome

Martin Morgan mtmorgan at fredhutch.org
Sat May 9 19:43:31 CEST 2015

On 05/09/2015 08:36 AM, Vincent Carey wrote:
> did you put this request on the forum?  did you follow the steps with
> BSforge and find
> an instruction that could not be followed or led to an error?  if you did,
> please put an
> account of that event on the support.bioconductor.org and you will get
> assistance.  read
> the posting guide and provide sessionInfo() so that your errors can be
> reproduced.

Vince is right that the question should probably be asked on the support forum, 
but for what it's worth I downloaded the file(?) to my current working directory

   url = "ftp://ftp.plantgdb.org/pub/Genomes/PpGDB/Ppatens_152.fa.gz"
   fl = basename(url)
   download.file(url, fl, mode="wb")

It's small enough that it can be read in to memory.

   dna = readDNAStringSet(fl)

but it would be convenient to have quick random access to to the sequences, so I 
exported it to "2bit' format

   library(BSgenome); library(rtracklayer)
   twobit = TwoBitFile(sub(".gz", ".2bit", fl)))
   export(dna, twobit)

and then I have ready access to the sequences, e.g.,

 > seqinfo(twobit)
Seqinfo object with 2106 sequences from an unspecified genome:
   seqnames       seqlengths isCircular genome
   scaffold_1        5387533       <NA>   <NA>
   scaffold_2        4973254       <NA>   <NA>
   scaffold_3        4236991       <NA>   <NA>
   scaffold_4        4046325       <NA>   <NA>
   scaffold_5        3779828       <NA>   <NA>
   ...                   ...        ...    ...
   scaffold_11864       1003       <NA>   <NA>
   scaffold_11874       1002       <NA>   <NA>
   scaffold_11881       1000       <NA>   <NA>
   scaffold_11890       1000       <NA>   <NA>
   scaffold_11893       1000       <NA>   <NA>
 > query = GRanges("scaffold_109", IRanges(seq(1, 1000, by=100), width=50))
 > getSeq(twobit, query)
   A DNAStringSet instance of length 10
      width seq
 > query$seq = getSeq(twobit, query)

Hope that's helpful; I might have made different decisions with a larger genome 
or on Windows, so if you re-post your question on the support forum (which I 
hope you do) it would be helpful to include that information as well as your 
intended use.


> On Fri, May 8, 2015 at 7:34 PM, Eric P <pedereri at gmail.com> wrote:
>> Hi
>> I have 2-3 genomes that are not listed that I would like to use with
>> bioconductor and I do not really understand how to prepare one properly. I
>> know you have to use BSforge, but after that I need some help. One of the
>> genomes is *Physcomitrella patens*, which is actually being updated at the
>> moment, so I am waiting for version 3.1 to come out, but if someone has
>> time they could add version 1.6 or 3.0.
>> However, the other two genomes I have to do myself as they will not be
>> published for a while so I could just as well try a third. Any help would
>> be appreciated, thanks. Also, if this was already posted I apologize but I
>> could not find enough information on this subject when I searched the
>> forums.
>> --
>> Cheers,
>> Eric
>>          [[alternative HTML version deleted]]
>> _______________________________________________
>> Bioc-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/bioc-devel
> 	[[alternative HTML version deleted]]
> _______________________________________________
> Bioc-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/bioc-devel

Computational Biology / Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N.
PO Box 19024 Seattle, WA 98109

Location: Arnold Building M1 B861
Phone: (206) 667-2793

More information about the Bioc-devel mailing list