Typing Human DNA Using Capillary Electrophoresis: Comparison of Slab Gel and Capillary Formats

Abstract

Capillary electrophoresis (CE) is a high resolution microanalytical technique which can be used to separate biological molecules such as DNA (1–3). Compared to conventional slab gel electrophoresis, CE provides rapid run times and similar mn-to-run precision. Slab gel electrophoresis of PCR products generally requires 2–5 hours for separation and detection. Thin-walled fused silica capillaries allow for greater heat dissipation and consequently higher voltages (as high as 30,000 Volts). An increase in voltage results in run times of approximately 30–50 minutes for PCR amplified short tandem repeat (STR) alleles or even larger restriction fragments (4). Instruments available on the market to date, however, only provide single column capabilities. Therefore, with a single column instrument 29–48 injections can be made in a twenty-four hour period. With auto-sampling capabilities, the amount of hands-on time is minimized Nevertheless, the current level of through-put cannot compete with manual or automated slab gel analysis. Development of multi-capillary instruments (24–96 capillary formats), will allow for high through-put analysis in the near future. Consequently, on a multi-capillary instrument greater than 3000 injections could be made in a single day.