New multiplexes for Europe-amendments and clarification of strategic development.

Recently, the ENFSI/EDNAP groups issued advice on the design of the next generation of STR multiplexes in order to encourage standardisation within Europe. As the result of collaborative experimentation within the EDNAP group, we demonstrated that the low molecular weight STRs had substantial benefits to detect degraded samples. We subsequently recommended adoption of three new mini-STR loci to improve the success rate of degraded DNA markers, concurrent with the reduction in size of the existing STR markers in current use. This also improves the discriminating power of the system which is important to improve the power of national DNA databases. Subsequent discussions have occurred with manufacturers and members of the ENFSI/EDNAP groups. Because significant time and investment is required to develop new multiplexes of 13+ STR loci, manufacturers indicated that it would be preferable to adopt a staged approach. Two differing, but parallel strategies have now emerged. The first strategy employs a 13 STR loci multiplex incorporating three mini-STRs into the current multiplex test. The second strategy employs a multiplex of six high molecular weight STRs (in current use), modified to provide smaller amplicons combined with an additional two loci of high discriminating power. Eventually, the two strategies will converge to provide a single multiplex of 15 STR loci. The process will be guided by the ENFSI/EDNAP groups.