Many of the current medical and genetics database on variants or mutations that cause diseases are primarily in the exons and the coding regions. Historically, identifying new genes and pathways relied on screening for mRNA, and most annotations are concerned with define what each mRNA does with the cell and the organism. As such, interpreting new and rare mutations or variants in the coding region is rather straightforward and potentially of high yield, when coupled to the existing database of disease pathways.
We believe that whole exome sequencing will likely play a prominent role, when it becomes very affordable, rapid and robust. Church lab and others have developed methods for selectively capturing exons from the genomic DNA using molecular inversion probes or high density arrays. PGP has chosen the method for using molecular inversion probes, which represent a more flexible and cost-effective tool for targeting any part of the genomic DNA.