Genotyping by Microdevice Electrophoresis

DNA genotyping has traditionally been performed by slab-gel electrophoresis. The method is well established, very effective and reliable, but inherently slow and labor intensive. Capillary gel electrophoresis is now becoming recognized as an important alternative to slabs since it offers higher throughput and automation (1 ). Nevertheless, the fast growing need for DNA analysis capacity due, for example, to the sequencing of entire genomes and the establishment of complex DNA data banks, seems to demand even more powerful DNA analysis tools. Microdevice electrophoresis is being increasingly explored since it may allow electrophoretic DNA analysis approaching the theoretical performance limits of the method due to unique sample loading characteristics and the employment of very short separation distances (2 ). It has already been demonstrated that genotyping can be performed 10-100 faster than on capillaries and slabs (see Subheading 3.4. ). In addition, the fabrication and operation of high-density electrophoretic microdevices for high-sample throughput should be straightforward. Microfabrication might also permit the total integration of entire sample processing sequences (e.g., PCR, sample cleanup, separation) on one single device, potentially leading to drastically decreased sample and reagent volumes, significantly less human interference, and increased speed of analysis (3 ).