This section contains FAQs that provide general information about how a new dbSNP build is triggered, how builds are scheduled, the difference between a dbSNP build and a genome build, the data changes that can occur between builds, as well as FAQs that will show you how to find old build data, or the date of an old build. There are FAQs in this section that describe sequence notation and explain strand orientation, and describe portions of the mapping process in detail. There are also FAQs in this section that can help you find missing or merged SNPs, tell you why a SNP merged or split, answer questions about submitted data or explain how dbSNP computes data – from determining ancestral alleles to calculating a double hit SNP.

To begin searching this section of the dbSNP FAQ Archive, you can:

Enter your search word(s) text in the text box at the top of the page and click on the “Go” button

OR

Click on any of the “dbSNP Build Process” sub-categories listed in the “Contents” section below to navigate to the sub-category of your choice. Once you are in the sub-category, you will be presented with a grey box containing the questions for the sub-category you selected. Clicking on a question in this list will allow you to navigate to the answer.

Contents

• What Triggers a New Build?
• The SNP Build Schedule/Notification of Build Release
• Data Changes that Occur Between Builds
• Lag Time between dbSNP Website and FTP Site Following Build
• The Difference Between the SNP Build and the Genome Build
• Using Old vs. New Build Data
• Finding Old Build Data
• Finding a Build Number Based on a Date and Vice Versa
• The dbSNP Mapping Process
• Merging RefSNP Numbers and RefSNP Clusters
• Ancestral Allele Data
• Average Allele Frequency Calculation
• Double Hit SNP Computation
• Hardy Weinberg Equilibrium Data
• Heterozygosity Data
• Linkage Disequilibrium Data
• dbSNP Haplotype Data
• dbSNP and Haplogroup Data
• dbSNP and Haplotype Tagged SNPs
• dbSNP and HapMap Data