Assembly of a large Y-STR haplotype database for the Czech population and investigation of its substructure

Phylogeographic review of Y chromosome haplogroups in Europe

The Y chromosome has been widely explored for the study of human migrations. Due to its paternal inheritance, the Y chromosome polymorphisms are helpful tools for understanding the geographical distribution of populations all over the world and for inferring their origin, which is really useful in forensics. The remarkable historical context of Europe, with numerous migrations and invasions, has turned this continent into a melting pot. For this reason, it is interesting to study the Y chromosome variability and how it has contributed to improving our knowledge of the distribution and development of European male genetic pool as it is today. The analysis of Y lineages in Europe shows the predominance of four haplogroups, R1b-M269, I1-M253, I2-M438 and R1a-M420. However, other haplogroups have been identified which, although less frequent, provide significant evidence about the paternal origin of the populations. In addition, the study of the Y chromosome in Europe is a valuable tool for revealing the genetic trace of the different European colonizations, mainly in several American countries, where the European ancestry is mostly detected by the presence of the R1b-M269 haplogroup. Therefore, the objective of this review is to compile the studies of the Y chromosome haplogroups in current European populations, in order to provide an outline of these haplogroups which facilitate their use in forensic studies.

Y-Chromosome Genetic Analysis of Modern Polish Population

The study presents a full analysis of the Y-chromosome variability of the modern male Polish population. It is the first study of the Polish population to be conducted with such a large set of data (2,705 individuals), which includes genetic information from inhabitants of all voivodeships, i.e., the first administrative level, in the country and the vast majority of its counties, i.e., the second level. In addition, the available data were divided into clusters corresponding to more natural geographic regions. Genetic analysis included the estimation of F_ST distances, the visualization with the use of multidimensional scaling plots and analysis of molecular variance. Y-chromosome binary haplogroups were classified and visualized with the use of interpolation maps. Results showed that the level of differentiation within Polish population is quite low, but some differences were indicated. It was confirmed that the Polish population is characterized by a high degree of homogeneity, with only slight genetic differences being observed at the regional level. The use of regional clustering as an alternative to counties and voivodeships provided a more detailed view of the genetic structure of the population. Those regional differences identified in the present study highlighted the need for additional division of the population by cultural and ethnic criteria in such studies rather than just by geographical or administrative regionalization.

Molecular diversity of 23 Y-chromosome short tandem repeat loci in the population of Tuzla Canton, Bosnia and Herzegovina

BACKGROUND

Tuzla Canton is the most populated region in the ethnically mixed territory of Bosnia and Herzegovina, whose genetic analysis could provide an insight into past demographic events.

AIM

Analysis of 23 Y-chromosome STR markers in the population of Tuzla Canton and investigation of the genetic relationship of the male population of the Tuzla Canton and that of the larger Bosnian and Herzegovinian population as well as neighbouring and other European populations.

SUBJECTS AND METHODS

The study was conducted among 100 unrelated healthy adult males from Tuzla Canton that have been genotyped using 23 Y-STR loci included in the PowerPlex Y23 kit. Statistical parameters such as haplotype diversity and allele frequencies were calculated, as well as the R_st-based genetic distances between the new dataset and those from Bosnia and Herzegovina and elsewhere, which were then visualised through multi-dimensional scaling plot and neighbour-joining phylogenetic tree analyses.

RESULTS

The PowerPlex Y23 kit has shown high discrimination capacity, as all 100 individuals have unique haplotypes. The newly incorporated loci seem to be highly informative. Population comparison reveals no statistically significant differences between the study population and the general Bosnian-Herzegovinian population, and between the study population and neighbouring populations.

CONCLUSION

These results could be used as an additional investigation of the genetic relationship between the regional populations in Bosnia and Herzegovina and neighbouring human populations, as well as for further human population and forensic genetics studies.

Croatian national reference Y-STR haplotype database

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.

A comparative phylogenetic study of genetics and folk music

Computer-aided comparison of folk music from different nations is one of the newest research areas. We were intrigued to have identified some important similarities between phylogenetic studies and modern folk music. First of all, both of them use similar concepts and representation tools such as multidimensional scaling for modelling relationship between populations. This gave us the idea to investigate whether these connections are merely accidental or if they mirror population migrations from the past. We raised the question; does the complex structure of musical connections display a clear picture and can this system be interpreted by the genetic analysis? This study is the first to systematically investigate the incidental genetic background of the folk music context between different populations. Paternal (42 populations) and maternal lineages (56 populations) were compared based on Fst genetic distances of the Y chromosomal and mtDNA haplogroup frequencies. To test this hypothesis, the corresponding musical cultures were also compared using an automatic overlap analysis of parallel melody styles for 31 Eurasian nations. We found that close musical relations of populations indicate close genetic distances (<0.05) with a probability of 82%. It was observed that there is a significant correlation between population genetics and folk music; maternal lineages have a more important role in folk music traditions than paternal lineages. Furthermore, the combination of these disciplines establishing a new interdisciplinary research field of "music-genetics" can be an efficient tool to get a more comprehensive picture on the complex behaviour of populations in prehistoric time.

Y-chromosomal diversity of the Valachs from the Czech Republic: model for isolated population in Central Europe

Aim

To evaluate Y-chromosomal diversity of the Moravian Valachs of the Czech Republic and compare them with a Czech population sample and other samples from Central and South-Eastern Europe, and to evaluate the effects of genetic isolation and sampling.

Methods

The first sample set of the Valachs consisted of 94 unrelated male donors from the Valach region in northeastern Czech Republic border-area. The second sample set of the Valachs consisted of 79 men who originated from 7 paternal lineages defined by surname. No close relatives were sampled. The third sample set consisted of 273 unrelated men from the whole of the Czech Republic and was used for comparison, as well as published data for other 27 populations. The total number of samples was 3244. Y-short tandem repeat (STR) markers were typed by standard methods using PowerPlex® Y System (Promega) and Yfiler® Amplification Kit (Applied Biosystems) kits. Y-chromosomal haplogroups were estimated from the haplotype information. Haplotype diversity and other intra- and inter-population statistics were computed.

Results

The Moravian Valachs showed a lower genetic variability of Y-STR markers than other Central European populations, resembling more to the isolated Balkan populations (Aromuns, Csango, Bulgarian, and Macedonian Roma) than the surrounding populations (Czechs, Slovaks, Poles, Saxons). We illustrated the effect of sampling on Valach paternal lineages, which includes reduction of discrimination capacity and variability inside Y-chromosomal haplogroups. Valach modal haplotype belongs to R1a haplogroup and it was not detected in the Czech population.

Conclusion

The Moravian Valachs display strong substructure and isolation in their Y chromosomal markers. They represent a unique Central European population model for population genetics.

Y-STR variation in Albanian populations: implications on the match probabilities and the genetic legacy of the minority claiming an Egyptian descent

Y chromosome variation at 12 STR (the Powerplex® Y system core set) and 18 binary markers was investigated in two major (the Ghegs and the Tosks) and two minor (the Gabels and the Jevgs) populations from Albania (Southern Balkans). The large proportion of haplotypes shared within and between groups makes the Powerplex 12-locus set inadequate to ensure a suitable power of discrimination for the forensic practice. At least 85% of Y lineages in the Jevgs, the cultural minority claiming an Egyptian descent, turned out to be of either Roma or Balkan ancestry. They also showed unequivocal signs of a common genetic history with the Gabels, the other Albanian minority practising social and cultural Roma traditions.