Improved fish species identification by use of lab-on-a-chip technology

Work reported here shows the outcome of improvements made to a published PCR-RFLP approach for fish species identification. The objective of the improved method was to replace the gel-electrophoretic steps for fragment separation, detection and analysis, by employing a chip-based capillary electrophoresis (CE) system. Fragment resolution on the system was sensitive, with detection of small fragments not observed with the published conventional gel-based method. Experimental repeatability was less than 3%, allowing species identification without the need to run reference materials with every sample. Using DNA admixtures, the discrimination of 5% salmon DNA in trout DNA was readily achieved. Results showed that the CE system was quick and easy to use, providing post-restriction digestion results for 12 samples within 40 min. This, along with the relatively low cost of the instrument, should make this method suitable for use in a wide range of analytical laboratories involved with species identification.