This directory contains alignments of the D. pseudoobscura assembly 
(dp2, Aug. 2003, BCM HGSC Freeze 1) to the D. melanogaster assembly 
(dm1, Jan. 2003, BDGP Release 3.1).

Files included in this directory:

  - axtNet directory: contains chained and netted alignments, i.e. the
    best chains in the genome, with gaps in the best chains filled in 
    by next-best chains where possible. 

  - pseudoobscura.chain.zip: chained blastz alignments. The chain format is 
    described in http://genome.ucsc.edu/goldenPath/help/chain.html.

  - pseudoobscura.net.zip: "net" file that describes rearrangements between 
    the species and the best D. pseudoobscura match to any part of the 
    D. melanogaster  genome.  The net format is described in 
    http://genome.ucsc.edu/goldenPath/help/net.html.

  - md5sum.txt: checksums of the files in this directory

The alignments in the axtNet directory are in "axt" format. For a 
description, see http://genome.ucsc.edu/goldenPath/help/axt.html.

The alignments were produced by the blastz alignment program, which 
is available from Webb Miller's lab at Penn State University 
(http://www.bx.psu.edu/miller_lab/). The blastz scoring matrix used was:

           A    C    G    T
      A   91 -114  -31 -123
      C -114  100 -125  -31
      G  -31 -125  100 -114
      T -123  -31 -114   91

with a gap open penalty of 400 and a gap extension penalty of 30.  The 
minimum score for an alignment to be kept was 3000 for the first pass  
and 2200 for the second pass, which restricted the search space to the 
regions between two alignments found in the first pass.

Each chromosome was divided into 10,010,000 base chunks with 10,000 bases
of overlap. The .lav format blastz output, which does not include
the sequence, was converted to .axt with lavToAxt. 

The axtNet alignments were processed with chainNet, netSyntenic,
and netClass written by Jim Kent at UCSC.

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If you plan to download a large file or multiple files from this 
directory, we recommend that you use ftp rather than downloading 
the files via our website. To do so, ftp to hgdownload.cse.ucsc.edu, 
then go to the directory goldenPath/dm1/vsDp2/. To download 
multiple files, use the "mget" command:

    mget <filename1> <filename2> ...
    - or -
    mget -a (to download all the files in the directory) 

All the files in this directory are freely available for public use.