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Currently, Forensic DNA research is conducted almost exclusively using capillary electrophoresis to determine the length of fragments containing Short Tandem Repeats (STRs). Over the past decade, developments in MPS (Massively Parallel Sequencing techniques, also known as Next Generation Sequencing) offered new possibilities for forensic DNA research. This thesis focusses on the preparation, validation and implementation of MPS and the accompanying data analysis. By MPS, the exact DNA sequence of STRs is determined often revealing additional variation on top of the fragment length resulting in an even more unique DNA profile. Sequence information provides more insight on the DNA molecules comprising a conventional DNA profile. With this information, a software could be developed to make a better distinction between genuine alleles and noise offering possibilities for analysis of unbalanced DNA mixtures which are often encountered in forensic casework.As alternative DNA marker to STRs, research was conducted to select microhaplotypes (multiple variable positions in a small fragment). The statistical power of a profile generated from these microhaplotypes turned out to be almost as strong as that of STRs without suffering from the known STR-artefacts thereby offering possibilities for interpretation of DNA mixtures.

Relevant for various areas of human genetics, Y-chromosomal short tandem repeats (Y-STRs) are commonly used for testing close paternal relationships among individuals and populations, and for male lineage identification. However, even the widely used 17-loci Yfiler set cannot resolve individuals and populations completely. Here, 52 centers generated quality-controlled data of 13 rapidly mutating (RM) Y-STRs in 14,644 related and unrelated males from 111 worldwide populations. Strikingly, >99% of the 12,272 unrelated males were completely individualized. Haplotype diversity was extremely high (global: 0.9999985, regional: 0.99836-0.9999988). Haplotype sharing between populations was almost absent except for six (0.05%) of the 12,156 haplotypes. Haplotype sharing within populations was generally rare (0.8% nonunique haplotypes), significantly lower in urban (0.9%) than rural (2.1%) and highest in endogamous groups (14.3%). Analysis of molecular variance revealed 99.98% of variation within populations, 0.018% among populations within groups, and 0.002% among groups. Of the 2,372 newly and 156 previously typed male relative pairs, 29% were differentiated including 27% of the 2,378 father-son pairs. Relative to Yfiler, haplotype diversity was increased in 86% of the populations tested and overall male relative differentiation was raised by 23.5%. Our study demonstrates the value of RMY-STRs in identifying and separating unrelated and related males and provides a reference database. Published 2014 Wiley Periodicals, Inc.**