Common SNPs (UCSC genome browser)

Question

[sandsol97]

I'm a little confused about common SNP subsets availabe in the UCSC genome browser. I was looking for relevant SNPs in a genome and each of these SNPs subsets build 142, 146 and 151 display different results.

However they have Identical definitions:

Common SNPs(138): SNPs that have a minor allele frequency of at least 1% and are mapped to a single location in the reference genome assembly. Frequency data are not available for all SNPs, so this subset is incomplete.

Common SNPs(151): SNPs that have a minor allele frequency of at least 1% and are mapped to a single location in the reference genome assembly. Frequency data are not available for all SNPs, so this subset is incomplete.

Yet they don't mention how they differ from each other. Example, I have been able to detect non-synonymous SNPs in SNPs(151), but not in SNPs(138) or SNPs(140). It is my understanding that the number is related to the number of single nucleotide variations.

My question is how do these dSNPs differ?

[desouzareis.r]

Hi, you can find helpful information here

Functional annotation varies from build to build because the reference genome sequence, upon which SNPs are mapped, is itself changing from assembly to assembly. During each assembly, the algorithms used to define “genes” are refined to improve accuracy...