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Many anthropological, linguistic, genetic and genomic analyses have been carried out to evaluate the potential impact that evolutionary forces had in shaping the present-day Sardinian gene pool, the main outlier in the genetic landscape of Europe. However, due to the homogenizing effect of internal movements, which have intensified over the past fifty years, only partial information has been obtained about the main demographic events. To overcome this limitation, we analyzed the male-specific region of the Y chromosome in three population samples obtained by reallocating a large number of Sardinian subjects to the place of origin of their monophyletic surnames, which are paternally transmitted through generations in most of the populations, much like the Y chromosome. Three Y-chromosome founding lineages, G2-L91, I2-M26 and R1b-V88, were identified as strongly contributing to the definition of the outlying position of Sardinians in the European genetic context and marking a significant differentiation within the island. The present distribution of these lineages does not always mirror that detected in ancient DNAs. Our results show that the analysis of the Y-chromosome gene pool coupled with a sampling method based on the origin of the family name, is an efficient approach to unravelling past heterogeneity, often hidden by recent movements, in the gene pool of modern populations. Furthermore, the reconstruction and comparison of past genetic isolates represent a starting point to better assess the genetic information deriving from the increasing number of available ancient DNA samples.

Haplogroup G, together with J2 clades, has been associated with the spread of agriculture, especially in the European context. However, interpretations based on simple haplogroup frequency clines do not recognize underlying patterns of genetic diversification. Although progress has been recently made in resolving the haplogroup G phylogeny, a comprehensive survey of the geographic distribution patterns of the significant sub-clades of this haplogroup has not been conducted yet. Here we present the haplogroup frequency distribution and STR variation of 16 informative G sub-clades by evaluating 1472 haplogroup G chromosomes belonging to 98 populations ranging from Europe to Pakistan. Although no basal G-M201* chromosomes were detected in our data set, the homeland of this haplogroup has been estimated to be somewhere nearby eastern Anatolia, Armenia or western Iran, the only areas characterized by the co-presence of deep basal branches as well as the occurrence of high sub-haplogroup diversity. The P303 SNP defines the most frequent and widespread G sub-haplogroup. However, its sub-clades have more localized distribution with the U1-defined branch largely restricted to Near/Middle Eastern and the Caucasus, whereas L497 lineages essentially occur in Europe where they likely originated. In contrast, the only U1 representative in Europe is the G-M527 lineage whose distribution pattern is consistent with regions of Greek colonization. No clinal patterns were detected suggesting that the distributions are rather indicative of isolation by distance and demographic complexities.

The distribution of Y-chromosomal single nucleotide polymorphism (SNP) haplogroups and short tandem repeat (STR) haplotypes was determined in a sample of 102 unrelated men of Arab origin from northwestern Algeria (Oran area). A total of nine different haplogroups were identified by a panel of 22 binary markers. The most common haplogroups observed in the Algerian population were E3b2 (45.1%) and J1 (22.5%). Y-STR typing by a 17-loci multiplex system allowed 93 haplotypes to be defined (88 were unique). Striking differences in the allele distribution and gene diversity of Y-STR markers between haplogroups could be found. In particular, intermediate alleles at locus DYS458 specifically characterized the haplotypes of individuals carrying haplogroup J1. All the intermediate alleles shared a common repeat sequence structure, supporting the hypothesis that the variant originated from a single mutational event.

Eight Y-chromosomal short tandem repeats (STRs)-DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393 and DYS385-were typed in a population sample (n=255) of unrelated Sicilian males from nine different towns on the main island and from the island of Pantelleria.

Eight Y-chromosome STR loci (DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393 and DYS385) were analysed in a sample of 236 unrelated males from four towns of Piedmont (Trino, Biella, Cavaglià, Postua). One hundred and fifty six different haplotypes were observed and 55 of them were not previously observed in the Y-STR Haplotype Reference Database (http://www.ystr.org/).

One of the many commercial technologies for genotyping single nucleotide polymorphisms (SNPs) is template direct dye-terminator incorporation with fluorescence-polarization (TDI-FP assay). It is a single-base extension assay followed by reading the fluorescence polarization values in an appropriate instrument. We have evaluated the suitability of the TDI-FP technique to detect haploid uniparentally inherited DNA polymorphisms on the nonrecombining portion of the Y chromosome. A sample of 47 individuals has been genotyped for 8 Y chromosome biallelic markers. The SNP typing was blindly duplicated by the denaturing high-performance liquid chromatography (DHPLC) technique for comparison. In the cases under examination the TDI-FP assay was able to resolve an allelic state fully. Such a result showed 100% concordance indicating how efficiently the TDI assay can be used to genotype Y chromosome DNA SNPs. However, a percentage of indeterminate genotypes remained unresolved by simple visual inspection: it varied from 0% to 11% depending on the SNP locus and on the success of amplification. This is consistent with previous findings. A maximum likelihood classificatory analysis allowed some of the indeterminate genotypes to be assigned and some potentially misclassified samples to be identified. Their percentage remains relatively high despite retyping and therefore alternative techniques for these noncompliant situations are required.

Eight Y-chromosomal short tandem repeats (STRs)--DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393, and DYS385--were typed in a population sample (n = 113) of unrelated males from seven different regions of Greece (Macedonia, Thessaly, Epirus, Central Greece, Peloponnese, Crete Island, and Chios Island).