Patterns of Y-STR variation in Italy

Joint Genetic Analyses of Mitochondrial and Y-Chromosome Molecular Markers for a Population from Northwest China

The genetic markers on mitochondria DNA (mtDNA) and Y-chromosome can be applied as a powerful tool in population genetics. We present a study to reveal the genetic background of Kyrgyz group, a Chinese ethnic group living in northwest China, and genetic polymorphisms of 60 loci on maternal inherited mtDNA and 24 loci on paternal inherited Y-chromosome short tandem repeats (Y-STRs) were investigated. The relationship between the two systems was tested, and the result indicated that they were statistically independent from each other. The genetic distances between Kyrgyz group and 11 reference populations for mtDNA, and 13 reference populations for Y-STRs were also calculated, respectively. The present results demonstrated that the Kyrgyz group was genetically closer to East Asian populations than European populations based on the mtDNA loci but the other way around for the Y-STRs. The genetic analyses could largely strengthen the understanding for the genetic background of the Kyrgyz group.

Reconstructing the genetic history of Italians: new insights from a male (Y-chromosome) perspective

BACKGROUND

Due to its central and strategic position in Europe and in the Mediterranean Basin, the Italian Peninsula played a pivotal role in the first peopling of the European continent and has been a crossroad of peoples and cultures since then.

AIM

This study aims to gain more information on the genetic structure of modern Italian populations and to shed light on the migration/expansion events that led to their formation.

SUBJECTS AND METHODS

High resolution Y-chromosome variation analysis in 817 unrelated males from 10 informative areas of Italy was performed. Haplogroup frequencies and microsatellite haplotypes were used, together with available data from the literature, to evaluate Mediterranean and European inputs and date their arrivals.

RESULTS

Fifty-three distinct Y-chromosome lineages were identified. Their distribution is in general agreement with geography, southern populations being more differentiated than northern ones.

CONCLUSIONS

A complex genetic structure reflecting the multifaceted peopling pattern of the Peninsula emerged: southern populations show high similarity with those from the Middle East and Southern Balkans, while those from Northern Italy are close to populations of North-Western Europe and the Northern Balkans. Interestingly, the population of Volterra, an ancient town of Etruscan origin in Tuscany, displays a unique Y-chromosomal genetic structure.

Population genetics of 17 Y-STR markers in Turkish Cypriots from Cyprus

We analyzed seventeen Y-chromosomal short tandem repeats (STRs) [DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a/b, DYS393, DYS391, DYS439, DYS635, DYS392, Y-GATA-H4, DYS437, DYS438, and DYS448] in 253 unrelated, male individuals from the Turkish Cypriot population of the Eastern Mediterranean island of Cyprus. While 206 out of the 253 haplotypes present in the dataset were unique, there are also 22 haplotypes that were observed in two individuals each, and 1 haplotype that was observed in three individuals. While no locus duplications or null alleles were observed in our dataset, we have detected 43 allelic variants in total, the majority of which (25 out of 253 haplotypes or 9.88%) comprised of .2 intermediate variants at the DYS458 locus (alleles 16.2, 17.2, 18.2, 19.2, and 20.2). For the 229 different haplotypes observed in the Turkish Cypriot dataset, the calculated discrimination capacity (DC) was 0.9051 and the haplotype diversity (HD) was 0.9992. The calculated average gene diversity (GD) values ranged from 0.3828 to 0.9631 for the DYS392 and DYS385a/b loci, respectively. Pairwise genetic distance comparisons of the Turkish Cypriot Y-STR dataset with those from the neighbouring (Turkey, Greece, Israel/Palestinian Authority area, Egypt and Italy) and relatively distant (Lithuania, Taiwan and Australia) countries through the use of analysis of molecular variance (AMOVA) and multi-dimensional scaling (MDS) analyses confirmed that our data do not deviate significantly from the typical core haplotypes of the Eastern Mediterranean region. The Turkish Cypriot Y-STR haplotype dataset will find an immediate use in the Committee on Missing Persons in Cyprus Project on the "Exhumation, Identification and Return of Remains of Missing Persons" and it is also expected to contribute to the establishment of forensic genetic services in North Cyprus.

Uniparental markers of contemporary Italian population reveals details on its pre-Roman heritage

Background

According to archaeological records and historical documentation, Italy has been a melting point for populations of different geographical and ethnic matrices. Although Italy has been a favorite subject for numerous population genetic studies, genetic patterns have never been analyzed comprehensively, including uniparental and autosomal markers throughout the country.

Methods/Principal Findings

A total of 583 individuals were sampled from across the Italian Peninsula, from ten distant (if homogeneous by language) ethnic communities — and from two linguistic isolates (Ladins, Grecani Salentini). All samples were first typed for the mitochondrial DNA (mtDNA) control region and selected coding region SNPs (mtSNPs). This data was pooled for analysis with 3,778 mtDNA control-region profiles collected from the literature. Secondly, a set of Y-chromosome SNPs and STRs were also analyzed in 479 individuals together with a panel of autosomal ancestry informative markers (AIMs) from 441 samples. The resulting genetic record reveals clines of genetic frequencies laid according to the latitude slant along continental Italy – probably generated by demographical events dating back to the Neolithic. The Ladins showed distinctive, if more recent structure. The Neolithic contribution was estimated for the Y-chromosome as 14.5% and for mtDNA as 10.5%. Y-chromosome data showed larger differentiation between North, Center and South than mtDNA. AIMs detected a minor sub-Saharan component; this is however higher than for other European non-Mediterranean populations. The same signal of sub-Saharan heritage was also evident in uniparental markers.

Conclusions/Significance

Italy shows patterns of molecular variation mirroring other European countries, although some heterogeneity exists based on different analysis and molecular markers. From North to South, Italy shows clinal patterns that were most likely modulated during Neolithic times.