Thanks Vanessa. That was really helpful.

How do I tell if something is insertion or deletion? Its obvious when a "class" 
is "deletion" or "insertion". However, it's a bit ambiguous in other classes.
1) What about in-del? Are the coordinates represented as deletions or insertion?
2) what about non-indel classes, such as microsatelite, mixed and mnp, they 
have locTypes of rangeInsertion/rangeDeletion. Do I interpret those coordinates 
like deletions and insertions?

Here is all possible combination of 'class' and 'loctype' in a dbsnp file.
class    locType
deletion    exact
deletion    range
in-del    between
in-del    exact
in-del    range
in-del    rangeDeletion
in-del    rangeInsertion
in-del    rangeSubstitution
insertion    between
insertion    exact
insertion    range
microsatellite    between
microsatellite    exact
microsatellite    range
microsatellite    rangeInsertion
mixed    between
mixed    exact
mixed    range
mixed    rangeDeletion
mnp    between
mnp    exact
mnp    range
mnp    rangeDeletion
mnp    rangeInsertion
mnp    rangeSubstitution
named    between
named    exact
named    range
named    rangeDeletion
named    rangeInsertion
single    between
single    exact
single    range
single    rangeDeletion
single    rangeInsertion
single    rangeSubstitution

Kyle

On 4/17/12 6:29 PM, "Vanessa Kirkup Swing" <[email protected]> wrote:

Hi Kyle,

Please see the answers below:


1) if start position is actually the 1st deleted base or the base before the 
start of the deletion.

With deletions, chromStart is the first deleted base which is not like the VCF 
format .

2) In the case of insertion, is start position is 1bp before the actual 
insertion event.

For insertions, note that when you add 1 to chromStart, chromStart becomes 1 
greater than chromEnd. So chromStart is the first base after the insertion and 
chromEnd is the last base before the insertion. This is kind of confusing, but 
in the end, the coordinate math for the length in reference bases is 0.

If you have further questions, please contact the list: [email protected].

Vanessa Kirkup Swing
UCSC Genome Bioinformatics Group


---------- Forwarded message ----------
From: Chang, Kyle <[email protected]>
Date: Tue, Apr 17, 2012 at 1:55 PM
Subject: Re: [Genome] How are ucsc dbsnp indel positions reported
To: Vanessa Kirkup Swing <[email protected]>
Cc: "[email protected]" <[email protected]>, "Kakkar, Nipun" 
<[email protected]>


Right I understand that the positions are all 0-based, and I need to add 1 to 
get the same start coordinate as the genome browser.

What I want to know is 1) if start position is actually the 1st deleted base or 
the base before the start of the deletion.
2) In the case of insertion, is start position is 1bp before the actual 
insertion event.


Kyle



On 4/17/12 3:48 PM, "Vanessa Kirkup Swing" <[email protected] 
<http://[email protected]> > wrote:

Hi Kyle,

Please see this FAQ on our coordinate system:

http://genome.ucsc.edu/FAQ/FAQtracks.html#tracks1


I hope that clarifies things for you. If you have further questions, please 
email the list: [email protected] <http://[email protected]> .

Vanessa Kirkup Swing
UCSC Genome Bioinformatics Group




---------- Forwarded message ----------
From: Chang, Kyle <[email protected] <http://[email protected]> >
Date: Tue, Apr 17, 2012 at 10:02 AM
Subject: [Genome] How are ucsc dbsnp indel positions reported
To: "[email protected] <http://[email protected]> " <[email protected] 
<http://[email protected]> >
Cc: "Kakkar, Nipun" <[email protected] <http://[email protected]> >


Hi,

I have a question on how indel coordinates are reported in dbsnp tables.

Here is a deletion record in dbsnp 135. Is 'start' always the 1st deleted
base or is it like the vcf format which the start is always 1bp before 1st
deleted base?

E.g.
131    chr1    61341695    61341699    rs146746778    0    +    TTTA    TTTA
-/TTTA    genomic    deletion

Fo insertion, is 'start' reported as 1bp before insertion? So in this case,
I imagine there's a CA insertion between 92536832 92536833 in 0-base
coordinates.

E.g.
161    chr1    92536832    92536832    rs72159935    0    +    -    -
-/CA    genomic    insertion

Best,
Kyle


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