While gene chips efficiently detect known single nucleotide variations at specific points in the genome, detecting previously unsuspected small variations in the genome often requires DNA sequencing. Sequencing technology advances in recent years have been remarkable; costs of high quality DNA sequencing are now approximately 1/100,000 of what they were five years ago.16 (Figure 1) Consequently, both biomedical research and clinical medicine have begun to take advantage of sequencing the protein coding regions of the genome (the exome), and even entire genomes. New sequencing machines can fit on a desktop and generate high quality sequence data in hours that took teams of individuals, with rooms of equipment, years to complete a decade ago.
