Automated and integrated system for high-throughput DNA genotyping directly from blood

An automated and integrated system for DNA typing directly from blood sampl es has been developed. The multiplexed eight-array system is based on capil lary microfluidics and capillary array electrophoresis. Three short-tandem- repeat loci, vWA, THO1, and TPOX, are coamplified simultaneously in a fused -silica capillary by a hot-air thermocycler. Blood is directly used as the sample for polymerase chain reaction (PCR) without any pretreatment. Modifi cations of standard protocols are necessary for direct PCR from blood. A pr ogrammable syringe pump plus a set of multiplexed liquid nitrogen freeze/th aw switching valves are employed for liquid handling in the fluid distribut ion network. The system fully integrates sample loading, PCR, addition of a n absolute standard, on-line injection of sample and standards, separation and detection. The genotypes from blood samples can be clearly identified i n eight parallel channels when the electropherograms are compared with that of the standard allelic ladder by itself. Regeneration and cleaning of the entire system prior to subsequent runs are also integrated into the instru ment. The instrumentation is compatible with future expansion to hundreds o f capillaries to achieve even higher throughput.