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In order to investigate Croatian mitochondrial DNA variability and to generate a national forensic reference database, complete control region sequences were generated for 200 randomly selected individuals. In general, almost exclusively Westeurasian lineages were found, associated with a high level of genetic diversity. The most frequent haplogroups were H (25.5%) and U (22%), followed by HV (11.5%), T (10%), N (8%), K, J, R (7.5% each). We report a yet undescribed sub-lineage of East Asian provenance that belongs to haplogroup A, which has been rarely described in the Westeurasian gene pool. The interpopulation comparison confirmed that Croatian mtDNA variability fits within a broader South and Southeastern Europe (SEE) maternal genetic landscape. Besides population genetic studies, the dataset will be used as national reference database in forensic and missing persons casework and provided via EMPOP to the forensic genetic community.

In order to implement X-chromosome short tandem repeat (X-STR) typing into routine forensic practice, reference database of a given population should be established. Therefore we extended already published data with additional 397 blood samples from unrelated Croatian citizens, and analyzed the total of 995 samples (549 male and 446 female) typed by Investigator® Argus X-12 Kit. To test genetic homogeneity of consecutively processed five historic-cultural regions covering the entire national territory, we calculated pairwise Fst genetic distances between regions based on allele and full haplotype frequencies. Since the comparison did not yield any statistically significant difference, we integrated STR profile information from all regions and used the whole data set to calculate forensic parameters. The most informative marker is DXS10135 (polymorphism information content (PIC = 0.929) and the most informative linkage group (LG) is LG1 (PIC = 0.996). We confirmed linkage disequilibrium (LD) for seven marker pairs belonging to LG2, LG3 and LG4. By including LD information, we calculated cumulative power of discrimination that amounted to 0.999999999997 in females and 0.999999005 in males. We also compared Croatia with 13 European populations based on haplotype frequencies and detected no statistically significant Fst values after Bonferroni correction in any LG. Multi- dimensional scaling plot revealed tight grouping of four Croatian regions amongst populations of southern, central and northern Europe, with the exception of northern Croatia. In this study we gave the first extensive overview of aberrant profiles encountered during Investigator® Argus X-12 typing. We found ten profiles consistent with single locus duplication followed by tetranucleotide tract length polymorphism. Locus DXS10079 is by far the most frequently affected one, presumably mutated in eight samples. We also found four profiles consistent with X-chromosome aneuploidy (three profiles with XXX pattern and one profile with XXY pattern). In conclusion, we established integral forensic Croatian X- chromosome database, proved forensic pertinence of Investigator® Argus X-12 Kit for the entire Croatian population and identified locus DXS10079 as a potential duplication hotspot.

Forensic evidence samples are routinely found as stains on various substrates, which may contain substances known to inhibit polymerase chain reaction (PCR). The goal of this study was to evaluate post-Chelex(®) 100 purification using powdered activated carbon (PAC). Mock crime scene DNA extracts were analyzed using quantitative PCR and short tandem repeat (STR) profiling to test the DNA recovery and inhibitor removal using PAC with those of the Amicon(®) Ultra 100K. For extracted bloodstains on soil and wood substrates, PAC and Amicon(®) Ultra 100K generated similar DNA yield and quality. Moreover, the two methods significantly decreased the concentration of humic substances and tannins compared to nonpurified extracts (p

The purpose of this study was to establish allele frequencies and forensic parameters for 20 STR loci (15 established STR loci and five additional ESS STR loci), as a maximum number of loci used for the production of the DNA profiles.