Hello Debra,

To calculate browser coordinates from our alignment files for alignments 
to the negative strand, you need to convert the numbers you see in the 
file. For alignments to the positive strand:

s hg18.chr5 161255235 226 + 180857866

You can simply read off the coordinates. Please see this previously 
answer mailing list question about this conversion:

http://www.soe.ucsc.edu/pipermail/genome/2007-September/014617.html

For the mouse entry in question:

s mm8.chr11 79819585 226 - 121798632

Corresponds to:
source: mm8.chr11
start: 79819585
size: 226
strand: -
source size: 121798632

To convert these numbers to Genome Browser coordinates, first subtract 
the start from the source size:

121798632 - 79819585 = 41979047

This is the right-most coordinate displayed in the browser. To get the 
left-most coordinate, subtract 226 from this number:

41979047 - 226 = 41978821

This yields coordinates: chr11: 41978821-41979047

This corresponds roughly to the results I see when blatting your 
sequence against mm8:


    BLAT Search Results

   ACTIONS      QUERY           SCORE START  END QSIZE IDENTITY CHRO STRAND  
START    END      SPAN
---------------------------------------------------------------------------------------------------
browser 
<../cgi-bin/hgTracks?position=chr11:41978827-41979037&db=mm8&ss=../trash/hgSs/hgSs_genome_b2a_67f830.pslx+../trash/hgSs/hgSs_genome_b2a_67f830.fa&hgsid=120087193>
 details 
<../cgi-bin/hgc?o=41978826&g=htcUserAli&i=../trash/hgSs/hgSs_genome_b2a_67f830.pslx+..%2Ftrash%2FhgSs%2FhgSs_genome_b2a_67f830.fa+YourSeq&c=chr11&l=41978826&r=41979037&db=mm8&hgsid=120087193>
 YourSeq          211     1   211   211 100.0%    11   -   41978827  41979037   
 211



Hopefully this information was helpful and answers your question. If you 
have further questions or require clarification feel free to contact the 
mailing list at [email protected].

Regards,

Pauline Fujita
UCSC Genome Bioinformatics Group
http://genome.ucsc.edu

[email protected] wrote:
> Hello,
>
> In extracting out orthologous sequences between human and mouse from the
> 17-way alignments I came across this alignment:
>
> a score=1971219.000000
> s hg18.chr5 161255235 226 + 180857866
> TTTTTTCTTT---ACAGGAGTAACAACTGTGCTCACCATGACAACATTGAGCATCAGTGCCAGAAACTCCCTCCCTAAGGTGGCTTATG
> CAACAGCTATGGATTGGTTTATTGCCGTGTGCTATGCCTTTGTGTTCTCAGCTCTGATTGAGTTTGCCACAGTAAACTATTTCACTAAGAGAGGTTATGCATGGGATGGCAAAAGTGTGGTTCCAGA
> AAAGGTAA-A----TGC-T
> s mm8.chr11  79819585 226 - 121798632
> TTCTCTCCTT---TTAGGAGTGACGACTGTTCTGACTATGACAACCTTGAGTATCAGTGCCAGAAATTCCCTCCCGAAGGTGGCTTATG
> CAACAGCTATGGACTGGTTTATTGCAGTATGCTATGCCTTTGTTTTCTCAGCTCTGATTGAGTTTGCCACAGTAAACTATTTCACCAAGAGAGGGTATGCGTGGGATGGCAAAAGCGTGGTTCCAGA
> AAAGGTAA-A----CAC-C
> i mm8.chr11 C 0 C 0
>
> However, it appears that the mouse sequence is actually from this
> coordinate: chr11:41948901-41949116. There appears to be a high level of
> homology in the vicinity of these two regions on mouse chromosome 11. The
> 28-way alignments provide a similar mouse coordinate region to that found
> in the 17-way alignment. Could you please advise on what the problem might
> be?
>
> Thank-you.
> Debra
>
> _______________________________________________
> Genome maillist  -  [email protected]
> http://www.soe.ucsc.edu/mailman/listinfo/genome
>   

_______________________________________________
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