The chips are down – genotyping on a plate

An exciting and powerful service, using a new tool to investigate the genetics of human diseases, is announced today [1st October]. MRC geneservice, located in Cambridge, UK, is now able to supply researchers with fast and sensitive Affymetrix SNP genotyping in order to identify genome-wide linkage of diseases to particular markers in the human genome.

The GeneChipâ Mapping Assay kit from Affymetrix enables genotyping of more than 11,500 single nucleotide polymorphisms (SNPs) on a single array using only 250 ng of human genomic DNA for each sample. These SNPs are used as bi-allelic genetic markers for the localization of genes underlying specific diseases by testing DNA samples from families with those conditions. The result is a highly informative genome-wide genetic map with an unprecedented resolution.. The high density of markers, the high call rate, accuracy and speed of the method represents a significant stride forward in genome mapping.
The team at MRC geneservice has a wealth of experience in using Affymetrix expression arrays and in conventional disease gene-hunting using genetic linkage. The team is now able to offer a highly customised and efficient Affymetrix SNP genotyping service for human mapping arrays, having already run more than 250 chips during service development. In addition, the simultaneous introduction of a top-quality processing pipeline makes this service a cost-effective solution for researchers who lack the technology, expertise and infrastructure to undertake these experiments in their own laboratories.

This high power and efficiency should give researchers the ability to more readily link disease to parts of the human genome where specific disease genes might lie. This is one of the necessary first steps in understanding if and how some people are more at risk of contacting genetic diseases. Eventually this understanding might lead to more finely tuned therapies.

Dr Sawcer from the University of Cambridge Neurology Unit who works on the genetic analysis of multiple sclerosis, explained that after some pilot project work on 20 samples: “The high genotyping success rate, genotyping accuracy and dense map of SNPs means that the Affymetrix chip is able to quickly and efficiently extract very nearly all the available linkage information from an affected sib pair.”