Hi Greg,

Thank you for your reply. It is very helpful. I am trying to build the 
chainFilter and netFilter from source. Could you please let me know which 
directory these two tools are under? I checked kent/src/utils but can't find 
them there. Thank you.

- Jia
________________________________________
From: Greg Roe [[email protected]]
Sent: Wednesday, April 25, 2012 4:32 PM
To: Zeng, Jia
Cc: [email protected]
Subject: Re: [Genome] How to interpret chain & net files in light of orthology

Hi Jia,

I would start by reading the help docs on chains and nets:

http://genome.ucsc.edu/goldenPath/help/chain.html
http://genome.ucsc.edu/goldenPath/help/net.html

Those explain chains and nets and how the files are constructed.

I'm not totally sure what you are expecting to see but are not. For example, if 
I click on the net showing at the position you listed (chr7:25681793-25788913), 
it has an ID of 5. If I look in the rbest.net file, I find the line 
corresponding to that, here:

fill 1730704 157395378 chr7 + 370509 158704532 id 5 score 11940049674 ali 
135239485 qDup 1095596 type top


If you are comfortable building some of our utilities from source 
(http://hgdownload.cse.ucsc.edu/downloads.html#source_downloads), here are 
command lines that extract the rbest chain that overlaps that region and the 
complete structure of the enclosing rbest net:

chainFilter hg19.panTro3.rbest.chain.gz -t=chr7 -tOverlapStart=25681792 
-tOverlapEnd=25788913 > HOXA_region.chain

netFilter hg19.panTro3.rbest.net.gz -t=chr7 -tOverlapStart=25681792 
-tOverlapEnd=25788913 > HOXA_region.net

chainFilter and netFilter both have many other options described in their usage 
messages.

For understanding the positive and negative strand entries, you may find this 
previous mailing list answer helpful: 
https://lists.soe.ucsc.edu/pipermail/genome/2011-November/027526.html

I hope that helps!


Please let us know if you have any additional questions: 
[email protected]<mailto:[email protected]>

-
Greg Roe
UCSC Genome Bioinformatics Group


On 4/23/12 2:35 PM, Zeng, Jia wrote:

Hi,

I'm trying to infer orthologous regions between two different species using the 
chain and/or net file provided by UCSC. To understand how to do this, I decided 
to use a
well conserved region (the HOXA cluster from human genome) as inquiry. This 
region's coordinate (panning from HOXA1 to HOXA13) is chr7:25681793-25788913 in 
hg19.
Due to HOX genes' high conservation level, I expect there to be a corresponding 
region in the Chimp genome.

To check whether this is indicated by the chain/net files, I downloaded the 
hg19.panTro3.rbest.chain and hg19.panTro3.rbest.net files. For some reason, I 
didn't locate
any chain/net that overlap with the aforementioned region although if I input 
the said region on genome browser and turned on the comparative genomics track. 
it seems
that the Chimp Alignment Net does exist for this region.

I suspect that I may have some fundamental misunderstanding about the files of 
interest and I also am not very clear about the practical difference between 
the rbest.chain
and rbest.net files. Your input will be greatly appreciated.

Best,
- Jia
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