Second-generation sequencing of forensic STRs using the Ion Torrent™ HID STR 10-plex and the Ion PGM™

Inter-laboratory evaluation of the EUROFORGEN Global ancestry-informative SNP panel by massively parallel sequencing using the Ion PGM™

“…Massively parallel sequencing (MPS) has the capacity to greatly enhance forensic DNA analysis by providing accurate sequence data for hundreds of loci resulting in a marked increase in the information gained from a single DNA test [11][12][13][14][15]. Initial assessments of MPS indicate that sequence data with sufficiently high coverage and 4 reliable genotypes can be produced for most loci.…”

Next generation sequencing and its applications in forensic genetics

“…The pyrosequencers were the only platforms with sufficient read length to sequence the core STR loci used in forensic genetics and to date, most of the forensic literature with NGS STR data were produced with pyrosequencing technology [62][63][64][65][66][67][68][69][70]. In a few reports, sequencing by synthesis [71][72][73] and recently also semiconductor sequencing [70,74] were used. The libraries were constructed directly by PCR or by adapter ligation as described in Fig.…”

“…Previously unknown STR alleles and more overall variability has been found by NGS of mainly complex and compound STRs [65,66,69], whereas few new alleles have been detected by sequencing of simple STRs [62,69,74]. Complex and compound STRs consist of different sub-repeats and, if the individual sub-repeats are polymorphic, the number of possible alleles will be much higher than in simple repeats (it is equivalent to having two STRs in a haplotype).…”

“…Sequencing of complex and compound STRs with many alleles of the same size may simplify mixture interpretation, if the contributors have alleles of the same size with different sequence compositions or if the true allele of the minor contributor has a different sequence than the stutter artifact of the major contributor. It was recently demonstrated that sequences from the minor contributor in 1:100 and 1:50 mixtures were detectable by NGS [74,76] -something that is not possible with the current PCR-CE technology. In these types of mixtures, the reads from the minor contributor will be difficult to separate from stutters and noise sequences, however, the mere fact that they could be identified opens up for new possibilities in mixture interpretation and it is certainly something that should be explored further.…”

“…Furthermore, Thermo Fisher Scientific is working on a panel of core forensic STRs, and an early version of this panel, the Ion Torrent TM HID STR 10-plex, has been tested by forensic laboratories [74]. The assays use the Ion AmpliSeq TM technology, where the PCR primers are partly degraded prior to adapter ligation.…”