This paper presents the authors' experiences in the use of mini-amplicon kits in cases that involve degraded skeletal remains, and it discusses issues in the use and limitations of short amplicons for increasing successful identifications from degraded skeletal remains.
The authors are employed by the International Commission on Missing Persons (ICMP), which was established in 1996 for the primary purpose of assisting in identifying approximately 40,000 persons missing in the course of the conflicts in the former Yugoslavia during 1992-1995 and in Kosovo in 1999. In recent years, there has been much attention and promise regarding the use of reduced-amplicon length STR typing for increasing the success of allele recovery from degraded DNA samples. Given the scale and nature of the DNA testing at the ICMP, the prospect of higher recovery of alleles from degraded DNA is appealing. Based on published primer sequences for shorter amplicons for STR loci found in commercial kits, the ICMP has developed and tested three novel multiplexes (a 7-plex, a 6-plex, and a 5-plex). These have been applied to casework samples in order to increase the recovery of amplicons from highly degraded samples. The kits target loci from large loci from large commercial multiplexes, with an average decrease in amplicon size of 144 bp. The ICMP "miniplexes" have provided substantially greater recovery of DNA data from a certain subset of difficult samples; however, the circumstances under which miniplexes provide additional data are restricted, and their advantages do not outweigh those of large commercial multiplexes for a majority of cases. The most effective use of miniplexes in DNA testing is in cases that involve a large-scale reassociation of comingled, partial skeletons recovered from secondary mass graves. Materials and methods are described. 1 table, 2 figures, and 8 references