This directory contains alignments of the rat assembly (rn3, Jun. 2003) 
to the mouse assembly (mm4, Oct. 2003).

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. 

  - axtTight directory: contains a highly conserved subset of the best 
    alignments for any part of the mouse genome. 

These alignments 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 10000 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. The axtTight alignments were 
processed with subsetAxt from Jim Kent using the matrix:

           A    C    G    T
      A  100 -200 -100 -200
      C -200  100 -200 -100
      G -100 -200  100 -200
      T -200 -100 -200  100

with a gap open penalty of 2000 and a gap extension penalty of 50. The 
minimum score was 3400. The axtTight subset covers 6% of the mouse genome 
while axtBest covers 40%.

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If you plan to download a large file or multiple files from this 
directory, we recommend 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/mm4/vsRn3. 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 usable for any purpose. 

      Name                    Last modified      Size  Description
      Parent Directory                             -   
      axtTight/               2003-11-04 14:43    -   
      axtNet/                 2003-11-04 14:39    -