Genetic landscape of the Hvar Island - highlight of a 50-year long bioanthropological research.

The paper presents an overview of the 50-year long bioanthropological research of the Hvar islanders and depicts the maternal and paternal genetic landscape of the Hvar population (mtDNA and NRY lineages) in more detail. MtDNA haplogroups were determined in 169 and NRY haplogroups in 407 autochthonous individuals from the Hvar Island. The relatively high level of diversity of mtDNA and NRY lineages has been observed, however with interesting deviations from both the maternal (F1b1 lineage) and paternal (Q2a1a lineage) perspective. Additionally, population substructuring revealed differences between Hvar communities (east-west substructuring), in line with the ethnohistoric background and observed migration patterns on the island. Genetic analysis of the Hvar islanders presents a highlight of the 50-year long anthropological research on this island and offers insight into the current genetic structure of Dalmatia, Croatia, shaped by dynamic and diverse population movements throughout history.

Association of perfluoroalkyl substances exposure with cardiometabolic traits in an island population of the eastern Adriatic coast of Croatia.

BACKGROUND: Exposure to perfluoroalkyl substances (PFAS), ubiquitous environmental contaminants, may be related to cardiometabolic diseases in adults. Studies in European populations to examine the association of PFAS exposure and comprehensive cardiometabolic traits and metabolic syndrome (MetS) are limited. METHODS: In this pilot cross-sectional study of a well-characterized adult population of the island of Hvar, situated off the eastern Adriatic coast of Croatia, we measured PFAS concentrations in plasma samples collected during 2007-2008 and examined their cross-sectional associations with cardiometabolic traits and MetS after adjustment of covariates (n = 122). PFAS investigated in this study included perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). RESULTS: The geometric mean (range) was 8.91 (2.36, 33.67) ng/mL for PFOS, 2.87 (1.03, 8.02) ng/mL for PFOA, 0.77 (0.25, 2.40) ng/mL for PFHxS, and 1.29 (0.48, 3.46) ng/mL for PFNA, with frequency of detection at 100%, 100%, 95.9%, and 100%, respectively. PFOS, PFOA, and PFNA concentrations were positively associated with the risk of MetS as defined by the Adult Treatment Panel III (ATP III) criteria, with estimated odds ratios and 95% confidence intervals at 1.89 (0.93, 3.86), 2.19 (0.88, 5.44), and 2.95 (1.12, 7.80), respectively, with only PFNA reaching statistical significance. PFNA concentrations were associated with increased risk of overweight or obesity. CONCLUSIONS: Background exposure to PFOS, PFOA, and PFNA was marginally associated with increased risk of MetS in this small study, and these results should be confirmed with a larger sample size and longitudinal follow-up.

Diversity of Y-chromosomal and mtDNA Markers Included in Mediscope Chip within Two Albanian Subpopulations from Croatia and Kosovo: Preliminary Data.

The aim of this preliminary study is to analyze genetic specificity of Kosovo Albanians comparing with neighboring populations using new genetic tool - MEDISCOPE gene chip, to investigate the feasibility of this approach. We collected 37 DNA samples (9 Croats, 17 Albanians from Croatia and 11 Albanians from Kosovo) from unrelated males born in Croatia and Kosovo. Additionally, samples were expanded with female individuals and mtDNA analysis included a total of 61 samples (15 Croats, 23 Albanians from Croatia and 23 Albanians from Kosovo). This pilot study suggests that the usage of the MEDISCOPE chip could be recognized as an efficient tool within recognition of the population genetic specificity even within extremely small sample size.

Maternal genetic heritage of Southeastern Europe reveals a new Croatian isolate and a novel, local sub-branching in the x2 haplogroup.

High mtDNA variation in Southeastern Europe (SEE) is a reflection of the turbulent and complex demographic history of this area, influenced by gene flow from various parts of Eurasia and a long history of intermixing. Our results of 1035 samples (488 from Croatia, 239 from Bosnia and 130 from Herzegovina, reported earlier, and 97 Slovenians and 81 individuals from Zumberak, reported here for the first time) show that the SEE maternal genetic diversity fits within a broader European maternal genetic landscape. The study also shows that the population of Zumberak, located in the continental part of Croatia, developed some unique mtDNA haplotypes and elevated haplogroup frequencies due to distinctive demographic history and can be considered a moderate genetic isolate. We also report seven samples from the Bosnian population and one Herzegovinian sample designated as X2* individuals that could not be assigned to any of its sublineages (X2a'o) according to the existing X2 phylogeny. In an attempt to clarify the phylogeny of our X2 samples, their mitochondrial DNA has been completely sequenced. We suppose that these lineages are signs of local microdifferentiation processes that occurred in the recent demographic past in this area and could possibly be marked as SEE-specific X2 sublineages.

Maternal genetic legacy of the eastern Adriatic island of Krk--an interplay of evolutionary forces and island's historical events in shaping the genetic structure of contemporary island population.

This study presents genetic diversity and structure of contemporary Krk islanders revealed by high-resolution mitochondrial DNA analysis on a sample of 132 unrelated autochthonous adults from seven different settlements and regions of the island. Relatively high level of haplogroup and haplotype diversity in the overall island sample is an indicator of numerous migrations and gene flows throughout the history. Expectedly, the results show the highest frequency of haplogroup H (33.3%), yet this value is much lower compared to different Croatian and other European mainland populations. An interesting finding refers to highly elevated frequencies of some haplogroups, otherwise rare in Croatia and most of the Europe, such as I (11.3%) and W (7.6%) in Krk population, especially pronounced in some settlements. At the level of settlements, many of the major European haplogroups were found to be absent from their mtDNA gene pools, whereas several others show a pronounced deviation from an average. Overall, our results suggest a tangled interplay of different evolutionary forces, such as founder effects and a few strong bottlenecks, presumably due to epidemics, which have occurred in various periods of the island's history. Cultural customs, such as frequent endogamy in some regions of the island during past centuries, have additionally shaped its genetic structure into the observed present-day diversity patterns.

Influence of evolutionary forces and demographic processes on the genetic structure of three Croatian populations: a maternal perspective.

BACKGROUND: Many Croatian islands are examples of genetic isolates, with low level of heterozygosity and high level of inbreeding, due to practice of endogamy. AIM: The aim was to study the genetic structure of two insular and one mainland population through high-resolution phylogenetic analysis of mitochondrial DNA (mtDNA). SUBJECTS AND METHODS: MtDNA polymorphisms were explored in 300 unrelated individuals from Mljet, Lastovo and the coastal city of Dubrovnik, based on SNP polymorphisms. RESULTS: All mtDNA haplogroups found in the sample were of typical European origin. However, the frequency distribution of their subclades differed significantly from other Croatian and European populations. MtDNA haplotype analysis revealed only two possible founder lineages on Mljet and six on Lastovo, accounting for almost half of the sample on both islands. The island of Mljet also has the lowest reported haplotype and nucleotide diversity among Croatian isolates and the island of Lastovo, a new sublineage of a usually quite rare U1b clade. CONCLUSION: The results can be explained by the effect evolutionary forces have on genetic structure, which is in line with the specific demographic histories of the islands. An additional research value of these two island isolates is the appearance of certain Mendelian disorders, highlighting their importance in epidemiological studies.

Separating the post-Glacial coancestry of European and Asian Y chromosomes within haplogroup R1a.

Human Y-chromosome haplogroup structure is largely circumscribed by continental boundaries. One notable exception to this general pattern is the young haplogroup R1a that exhibits post-Glacial coalescent times and relates the paternal ancestry of more than 10% of men in a wide geographic area extending from South Asia to Central East Europe and South Siberia. Its origin and dispersal patterns are poorly understood as no marker has yet been described that would distinguish European R1a chromosomes from Asian. Here we present frequency and haplotype diversity estimates for more than 2000 R1a chromosomes assessed for several newly discovered SNP markers that introduce the onset of informative R1a subdivisions by geography. Marker M434 has a low frequency and a late origin in West Asia bearing witness to recent gene flow over the Arabian Sea. Conversely, marker M458 has a significant frequency in Europe, exceeding 30% in its core area in Eastern Europe and comprising up to 70% of all M17 chromosomes present there. The diversity and frequency profiles of M458 suggest its origin during the early Holocene and a subsequent expansion likely related to a number of prehistoric cultural developments in the region. Its primary frequency and diversity distribution correlates well with some of the major Central and East European river basins where settled farming was established before its spread further eastward. Importantly, the virtual absence of M458 chromosomes outside Europe speaks against substantial patrilineal gene flow from East Europe to Asia, including to India, at least since the mid-Holocene.