In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent.

To test for human population substructure and to investigate human population history we have analysed Y-chromosome diversity using seven microsatellites (Y-STRs) and ten binary markers (Y-SNPs) in samples from eight regionally distributed populations from Poland (n = 913) and 11 from Germany (n = 1,215). Based on data from both Y-chromosome marker systems, which we found to be highly correlated (r = 0.96), and using spatial analysis of the molecular variance (SAMOVA), we revealed statistically significant support for two groups of populations: (1) all Polish populations and (2) all German populations. By means of analysis of the molecular variance (AMOVA) we observed a large and statistically significant proportion of 14% (for Y-SNPs) and 15% (for Y-STRs) of the respective total genetic variation being explained between both countries. The same population differentiation was detected using Monmonier's algorithm, with a resulting genetic border between Poland and Germany that closely resembles the course of the political border between both countries. The observed genetic differentiation was mainly, but not exclusively, due to the frequency distribution of two Y-SNP haplogroups and their associated Y-STR haplotypes: R1a1*, most frequent in Poland, and R1*(xR1a1), most frequent in Germany. We suggest here that the pronounced population differentiation between the two geographically neighbouring countries, Poland and Germany, is the consequence of very recent events in human population history, namely the forced human resettlement of many millions of Germans and Poles during and, especially, shortly after World War II. In addition, our findings have consequences for the forensic application of Y-chromosome markers, strongly supporting the implementation of population substructure into forensic Y chromosome databases, and also for genetic association studies.

Different regional populations from Poland were studied in order to assess the genetic heterogeneity within Poland, investigate the genetic relationships with other European populations and provide a population-specific reference database for anthropological and forensic studies. Nine Y-chromosomal microsatellites were analysed in a total of 919 unrelated males from six regions of Poland and in 1,273 male individuals from nine other European populations. AMOVA revealed that all of the molecular variation in the Polish dataset is due to variation within populations, and no variation was detected among populations of different regions of Poland. However, in the non-Polish European dataset 9.3% ( P<0.0001) of the total variation was due to differences among populations. Consequently, differences in R(ST)-values between all possible pairs of Polish populations were not statistically significant, whereas significant differences were observed in nearly all comparisons of Polish and non-Polish European populations. Phylogenetic analyses demonstrated tight clustering of Polish populations separated from non-Polish groups. Population clustering based on Y-STR haplotypes generally correlates well with the geography and history of the region. Thus, our data are consistent with the assumption of homogeneity of present-day paternal lineages within Poland and their distinctiveness from other parts of Europe, at least in respect to their Y-STR haplotypes. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00439-002-0728-0.

One of the stages of dealing with biological material submitted to forensic laboratories is species identification. The aim of the present work was to validate and assess the possibility of applying sequence analysis of the region coding cytochrome b as a method of species identification in the field of forensic science. DNA originating from individuals from major phyla of vertebrates was isolated by the organic method from various specimens. Extracted DNA was subjected to PCR and direct cycle sequencing using a universal pair of primers. The validation process, performed according to TWGDAM recommendations, revealed that the technique is a very sensitive and reliable method of species identification allowing analysis of tiny amounts of material and also degraded material, and can be useful in the field of forensic genetics. The case example presented here, concerning the determination of species origin of biological evidence collected from fatal road accident, confirms that analysis can be carried out even when there is no reference sample, and the sequences obtained can be assessed through analysis of their similarity to sequences for cytochrome b present in DNA databases.

There is a necessity for deceased identification as a result of many accidents and sometimes bones are the only accessible source of DNA. So far, a universal method that allows for extraction of DNA from materials at different stages of degradation does not exist. The aims of this study were: the comparison of three methods of DNA extraction from bones with different degree of degradation and an evaluation of the usefulness of these methods in forensic genetics. The efficiency of DNA extraction, the degree of extract contamination by polymerase chain reaction (PCR) inhibitors and the possibility of determining the STR loci profile were especially being compared. Nuclear DNA from bones at different states of degradation was isolated using three methods: classical, organic phenol–chloroform extraction, DNA extraction from crystal aggregates and extraction by total demineralisation. Total demineralisation is the best method for most cases of DNA extraction from bones, although it does not provide pure DNA. DNA extraction from aggregates removes inhibitors much better and is also a good method of choice when identity determination of exhumed remains is necessary. In the case of not buried bones (remains found outside) total demineralisation or phenol–chloroform protocols are more efficient for successful DNA extraction.Electronic supplementary materialThe online version of this article (doi:10.1007/s00414-011-0590-5) contains supplementary material, which is available to authorized users.