[Correlations between haplogroup membership and Y-STR haplotype as a potential measure of quality control in forensic examinations]. / Zaleznosci pomiedzy przynaleznoscia haplogrupowa a haplotypem Y-STR jako potencjalny element kontroli poprawnosci analiz w medycynie sadowej.

A correlation between particular Y-STR alleles from the so-called "minimal haplotype" and haplogroup membership of the Y chromosome was tested. We collected 146 Y chromosomes from haplogroups R1*, R1a1* and 1* and estimated the frequency of Y-STR alleles in each haplogroup. We then used different algorithms to assign a haplogroup to a haplotype, and tested their accuracy. Generally, a method based on calculation of haplotype similarity using the highest allele frequencies as modal values and assigning a score to each locus based on a ratio of allele frequencies turned out to give the most precise matches. However, using the same rules for Y chromosomes from other populations did not allow for precise estimation of their Y chromosome haplogroup frequencies. Possible explanations for this failure include interpopulation differences in haplotypes correlated with particular haplogroups, as well as a relatively small number of chromosomes analyzed. Potential uses for the presented method in forensics were also described.

[A comparison of the Bluestar and luminol effectiveness in bloodstain detection]. / Porównanie efektywnosci odczynnika Bluestar i luminolu w wykrywaniu sladów krwawych.

The objective of the present study was to compare the effectiveness of two chemical agents--Bluestar and luminol--in detection of bloodstains. The experiments were performed to test for bloodstain detection sensitivity, chemical stability and to investigate the effect of both reagents on DNA typing. During this study, the authors prepared serial dilutions (1:2 to 1:10 000 000) of fresh blood, as well as dilutions of 25-year old blood on Whatman 3MM blotting paper. Additional dilutions of fresh blood were spotted on a glass surface. The experiments showed very similar results for both investigated reagents, although the Bluestar solution proved to be more stable (at least 7 days after the preparation) as compared to luminol (stable for not more than 24 hours). Both reagents showed a higher sensitivity for diluted bloodstains on a glass surface than for similar stains on filter paper. The investigators also demonstrated that multiplex amplification of DNA was feasible after Bluestar or luminol treatment, although the detected bloodstains might be too diluted to allow for effective DNA extraction and amplification.

[Phylogeographic approach in the interpretation of mitochondrial DNA sequencing results in forensics]. / Zastosowanie analizy filogeograficznej w interpretacji wyników sekwencjonowania mitochondrialnego DNA dla celów sadowych.

In recent years, forensic mitochondrial DNA analysis has been undertaken from an evolutionary perspective. In particular, the phylogeographic approach based on a phylogenetic analysis of the spatial distribution of mitochondrial haplotypes and haplogroups appears to be a useful tool in the interpretation of identification cases. In this study, the phylogeographic approach has been employed in the analysis of three difficult forensic cases, where single nucleotide, homoplasmic differences were found between the reference and evidentiary haplotypes. mtDNA sequence variation has been examined by the control region (HVS I and HVS II) direct sequencing. Additionally, in order to clarify the subhaplogroup status of the selected haplotypes, DNA sequences of entire mitochondrial genomes obtained from two samples representing J1b subclade have been analyzed.

Low variability of the POLG (CAG)n repeat in north Eurasian populations.

We investigated the frequency of different repeat-length alleles of the trinucleotide CAG microsatellite repeat in the coding sequence of the nuclear gene for the catalytic subunit of mitochondrial DNA polymerase gamma (POLG) in 12 ethnic groups from northern Eurasia. The population sample consisted of 1,330 individuals from 3 large geographic areas: Europe, Southwest Asia, and Siberia/East Asia. We found that the 10-repeat allele of the POLG gene is the most frequent in all analyzed populations, with a frequency of 88-96%. The heterozygosity level ranges from 22% in Europe to 13.6% in Southwest Asia with the lowest value of 7.4% in Siberia/East Asia. The present study provides evidence of clinal distribution of POLG gene heterozygosity in North Eurasian populations. In general, we found an extremely low variability of the trinucleotide CAG microsatellite repeat, suggesting that purifying selection acts against deleterious alleles, although low mutability of the repeated region cannot be ruled out.