A reference Y-chromosome short tandem repeat (STR) haplotype database is needed for Y-STR match interpretation as well as for national and regional characterization of populations. The aim of this study was to create a comprehensive Y-STR haplotype database of the Croatian contemporary population and to analyze substructure between the five Croatian regions. We carried out a statistical analysis of the data from previously performed genetic analyses collected during routine forensic work by the Forensic Science Centre "Ivan Vučetić". A total of 1,100 unrelated men from eastern, western, northern, southern and central Croatia were selected for the purpose of this study. Y-STRs were typed using the AmpFISTR Yfiler PCR amplification kit. Analysis of molecular variance calculated with the Y chromosome haplotype reference database online analysis tool included 16 population samples with 20,247 haplotypes. A total of 947 haplotypes were recorded, 848 of which were unique (89.5%). Haplotype diversity was 0.998, with the most frequent haplotype found in 9 of 1,100 men (0.82%). Locus diversity varied from 0.266 for DYS392 to 0.868 for DYS385. Discrimination capacity was 86.1%. Our results suggested high level of similarity among regional subpopulations within Croatia, except for mildly different southern Croatia. Relative resemblance was found with Bosnia and Herzegovina and Serbia. Whit Atheys' Haplogroup Predictor was used to estimate the frequencies of Y-chromosome haplogroups. I2a, R1a, E1b1b and R1b haplogroups were most frequent in all Croatian regions. These results are important in forensics and contribute to the population genetics and genetic background of the contemporary Croatian population.

Human Y-short tandem repeats (STRs) are tandem repeat arrays of two to seven base pair units on non-recombining region (NRY) of the human Y chromosome. Studies on Y-STR are interesting in both population genetics and forensics. The aim of this study was to investigate the population genetic properties of 17 STR loci on Y chromosome in the northern Croatia region. We carried out a statistical analysis of the data from previously performed genetic analysis collected during routine forensic work by the Forensic Science Centre "Ivan Vučetić". A total of 220 unrelated healthy men from northern Croatia were selected for the purpose of this study. Genomic DNA was extracted using Chelex procedure from FTA(®) cards. Y-chromosomal STRs were determined using the AmpFISTR Yfiler PCR amplification kit. The haplotype frequencies were determined by direct counting and analyzed using Arlequin 3.1 and analysis of molecular variance calculated with the Y chromosome haplotype reference database online analysis tool. A total of 210 haplotypes were identified, 200 of which were unique. Total haplotype diversity was 0.995. Locus diversity varied from 0.331 for DYS392 to 0.783 for DYS385 locus. Allele frequencies diversity was 0.662. Discrimination capacity was 95.7%. The use of European minimal haplotype set indicated the most resemblance of this population to the Croatian capital of Zagreb, with modest resemblance to Bosnia and Herzegovina, Serbia and Hungary. This article provides the first overview of the Y chromosome STR variability in northern Croatia, thus providing the referent point for any future forensic and genetic epidemiology efforts in this region.

This is the first description of Y chromosome haplotyping of the population of eastern Croatia, which may serve as a basis for genetic epidemiology and forensic studies. Further studies are needed for characterization of the genetic structure of the Y-chromosome in the modern Croatian population.