## Description

This track displays the SNPs used in genotyping platforms.

## Affymetrix 500K (250K Nsp and 250K Sty)

This annotation displays the SNPs available for genotyping with the GeneChip Human Mapping 500K Array Set from Affymetrix. It is comprised of two arrays: Nsp and Sty, which contain approximately 262,000 and 238,000 SNPs, respectively.

## Affymetrix 100K (50K HindIII and 50K XbaI)

This annotation displays the SNPs available for genotyping with the GeneChip Human Mapping 100K Array Set from Affymetrix. It is comprised of two 50K arrays: HindIII and XbaI.

## Affymetrix 10K

This annotation displays the SNPs available for genotyping with the GeneChip Human Mapping 10K Array Sets from Affymetrix. There are two versions of the 10K array; each contains approximately 10,000 SNPs.

## Illumina 300K

This annotation displays the SNPs available for genotyping with Illumina's HumanHap300 BeadChip. The HumanHap300 contains over 317,000 tagSNP markers derived from the International HapMap Project.

## References

Further information on the Affymetrix arrays is available at these sites:

- 500K
- 100K
- 10K
- 10K v2

Further information on the Illumina array is available from Illumina.

## Methods

Position, strand, and polymorphism data were obtained from Affymetrix and supplemented with links to corresponding dbSNP rsIDs based on a positional lookup into dbSNP build 125. In fewer than 2% of the cases, a dbSNP rsID was not present in dbSNP build 125 at the Affymetrix array position. Reference allele information was retrieved from the UCSC database based on Affymetrix position and strand data.
Illumina data were supplied as rsIDs and was supplemented with position, strand, and polymorphism data based on a name lookup into dbSNP build 125. Reference allele information was retrieved from the UCSC database based on dbSNP position and strand data.

## Credits

Thanks to Venu Valmeekam from Affymetrix and Jeff Ohmen from Illumina for providing these data.