Hi Jiangtao,

We do not assign any of the positions for the SNPs shown in the Genome 
Browser; we take the positions directly from dbSNP.  See the "All 
SNPs(132)" track description page for more information.  To get to the 
track description page, go to the hg19 browser 
(http://genome.ucsc.edu/cgi-bin/hgTracks?org=Human&db=hg19), scroll down 
to "Variation and Repeats" and click the blue track name.  Under "Data 
Sources and Methods" you will see exactly where the data comes from.

I do see that the chr1 position is not displayed on dbSNP's page for 
rs3115865.  I am less familiar with dbSNP's display conventions than 
with the Genome Browser display, and I am not sure why they don't 
display the chr1 location for that SNP.  In the Genome Browser, 
rs3115865 is not displayed by default in the "All SNPs" track, because 
by default a filter is applied so that SNPs with a weight greater than 1 
are not displayed (this can be changed in the track controls, however).

I suggest contacting dbSNP about your questions below, as well as 
checking out the SNP FAQ Archive at dbSNP for more information on how to 
interpret dbSNP's data:
http://www.ncbi.nlm.nih.gov/books/NBK3848/

--
Brooke Rhead
UCSC Genome Bioinformatics Group


On 05/28/11 17:26, Tao Jiang wrote:
> Dear Rhead,
> 
> For the first example, what record should I keep?
> when I look the rsID 3115865 in dbSNP
page(http://www.ncbi.nlm.nih.gov/projects/SNP/snp_ref.cgi?rs=3115865), I
cannot find the chromosome position in the dbSNP page. Why you assign
741579 on chr1 for this rsID? While for the second rsID, I found the
right chr position for it.
> 
> Did you have a detailed illustration on the UCSC FAQ website showing
why you keep two(sometimes three or more) rsID for the identical chr
position?
> 
> For example, for the three records for one chr position, which should
> I keep, the first or the last one, or none of them is a confident SNP???
> 
> 585   chr1    12479   12480   rs62028715      0       +       C       C       
> C/G     genomic single  unknown 0       0       unknown exact   3       
> MultipleAlignments      BCMHGSC_JDW,    0                               
> 585   chr1    12479   12480   rs78725323      0       -       C       C       
> C/G     genomic single  unknown 0       0       unknown exact   3       
> MultipleAlignments      ENSEMBL,        1       C,      2.000000,       
> 1.000000,       maf-5-some-pop,maf-5-all-pops
> 585   chr1    12479   12480   rs78735090      0       +       C       C       
> C/G     genomic single  by-frequency    0.48    0.09798 unknown exact   3     
>   MultipleAlignments      1       ENSEMBL,        2       G,C,    
> 4.000000,6.000000,      0.400000,0.600000,      maf-5-some-pop,maf-5-all-pops
> 
> But for the SNP on the following chr position:
> 585   chr1    10439   10440   rs112155239     0       +       C       C       
> A/C     genomic single  unknown 0       0       unknown exact   1             
>   1       BCM-HGSC-SUB,   0                               
> 585   chr1    10439   10440   rs112766696     0       +       C       C       
> -/C     genomic deletion        unknown 0       0       unknown exact   1     
>           1       BUSHMAN,        2       -,C,    1.000000,1.000000,      
> 0.500000,0.500000,
> 
> which record should I regard as confident? for they both have no
"MultipleAlignments" annotation.
> 
> I am eagerly to know all the details and which record(or rsID) should
> 
I consider as confident.
> 
> 
> All my best,
> 
> Jiangtao
> 
> BGI-Shenzhen
> 
> 
> On May 28, 2011, at 9:01 AM, Brooke Rhead wrote:
> 
>> Hi Jiangtao,
>>
>> The engineer who works on SNPs here took a quick look at your examples.  For 
>> the first one, there may have been a strand error that caused dbSNP to fail 
>> to cluster the newer SNP (rs61770168) together with the older SNP 
>> (rs3115865).  For the second example, you may just want to ignore 
>> rs28658281, since it aligns to multiple places in the genome and has been 
>> given a higher weight by dbSNP.
>>
>> In both cases, you should check out dbSNP's pages (which are linked on the 
>> details pages in the Genome Browser).  For instance:
>> http://www.ncbi.nlm.nih.gov/projects/SNP/snp_ref.cgi?rs=3115865
>>
>> There you can see the full report on each reference SNP (which start with an 
>> "rs" -- we only show reference SNPs in the Genome Browser), and you can look 
>> at the list of submitter SNPs (which start with "ss") that were used to 
>> determine each reference SNP.
>>
>> You might also want to report these cases directly to dbSNP at 
>> [email protected].
>>
>> I hope this is helpful.  If you have further questions for UCSC, please feel 
>> free to contact us again at [email protected].
>>
>> --
>> Brooke Rhead
>> UCSC Genome Bioinformatics Group
>>
>>
>>
>> On 05/26/11 21:58, Tao Jiang wrote:
>>> Dear UCSC bioinformatic scientists:
>>> When use the file "snp132.txt.gz" downloaded from UCSC, I found a confusion 
>>> question: Why the SNPs that have exactly the same start and end coordinates 
>>> have different rsID, and sometimes have different allele frequency? Which 
>>> record is the refSNP record from NCBI dbSNP 132?
>>> The following are two examples:
>>> 1. 590     chr1    741578  741579  rs3115865       0       -       T       
>>> T       A/G     genomic single  by-cluster,by-hapmap    0       0       
>>> unknown exact   3       590     chr1    741578  741579  rs61770168      0   
>>>     +       T       T       C/T     genomic single  unknown 0       0       
>>> unknown exact   1               1    2. 707      chr22   16050993        
>>> 16050994        rs7288968       0       +       G       G       C/G     
>>> genomic single  by-cluster,by-2hit-2allele,by-hapmap    0       0       
>>> unknown exact   1               2       BCM_SSAHASNP,CSHL-HAPMAP,       0   
>>>                             
>>> 707 chr22   16050993        16050994        rs28658281      0       -       
>>> G       G       C/G     genomic single  by-cluster,by-frequency 0.375   
>>> 0.216506        unknownexact    3       MultipleAlignments      6       
>>> BCM-HGSC-SUB,BCMHGSC_JDW,BGI,ENSEMBL,HGSV,SSAHASNP,     2       G,C,    
>>> 6.000000,2.000000,      0.750000,0.250000,      
>>> maf-5-some-pop,maf-5-all-pops
>>> I am looking forward to hearing from you as soon as possible. Thanks a lot!
>>> All my best,
>>> Jiangtao
>>> BGI-Shenzhen
>>> _______________________________________________
>>> Genome maillist  -  [email protected]
>>> https://lists.soe.ucsc.edu/mailman/listinfo/genome
> 
_______________________________________________
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