The development of mini pentameric STR loci for rapid analysis of forensic DNA samples on a microfluidic system

There is increasing interest in developing methods for portable DNA analysis in mass disasters and criminal identification. Currently most forensic STR DNA analysis is performed by CE; however, these instruments are not portable and require long sample run times. One potential solution is the development of microfluidic systems for DNA typing. Unfortunately, fairly long (ca. 20 cm) separation channels are usually required for the proper resolution of multiplexed STR loci used in human identification. Commercially available systems like the Agilent 2100 Bioanalyzer have a small footprint and utilize chips with shorter channels and reduced resolution. Such portable systems might be valuable for evidence screening in remote locations. However, due to their lower resolution, most standard 4 base STR loci and their inherent 2 base variants will not resolve on such systems. In this paper, we discuss the development of reduced length pentameric (5 base) STR amplicons. Pentameric STRs have fewer variant alleles and are easier to separate due to the wider spacing between alleles. By incorporating novel denaturing sieving polymers in a short microfluidic channel, we demonstrate efficient separations on these chips. Such an approach can serve as a useful tool for rapid microfluidic DNA typing.