Analysis of a genetic isolate: the case of Carloforte (Italy).

We reviewed data collected during several studies concerning the genetic isolate of Carloforte (Sardinia, Italy) and analyzed new data on Y-chromosome markers. Carloforte is also a language island, where people still speak Tabarchino, an archaic form of Ligurian dialect. Demographic data indicate that, in the early years of its history, the Carloforte population was characterized by a high degree of endogamy and consanguinity rates that started to decrease around 1850, when marriages with Sardinian people began to occur more frequently. Cultural factors, mainly language, account for the high endogamy. Genetic data from classical markers, mtDNA, and Y-chromosome markers confirmed the strong isolation of the Carloforte population, which appears significantly different from the neighboring population of Sardinia. Analysis of mtDNA emphasizes the crucial aspect of sampling strategy-two different samplings of the same population (one based on founder surnames; the other based on grandparents' criterion) gave different results. Founder surnames sampling is not affected by recent events, and therefore it better describes the ancestral population, whereas, grandparents' criterion sampling gives a picture of the present population, shaped by more recent events, such as migration and gene flow. This review further supports the notion that a comprehensive approach, including a detailed knowledge of the history of the population and the collection of different samplings, is essential in anthropology for reconstructing past and recent events that contributed to establishing the present genetic structure of the population. Likewise, it is essential in medical genetics to identify genes involved in complex diseases. An ideal scenario is offered by a genetic isolate with a recent, and well-documented, history, such as Carloforte, that can ba a paradigm for this type of investigation.

Genetic markers and explosive leg-muscle strength in elite Italian soccer players.

AIM: The aim of the present paper was to investigate the relationships between polymorphisms in ACTN3, ACE and BDKRB2 genes, soccer performance, and explosive leg-muscle strength in Italian soccer players. METHODS: We examined 42 top-level Italian soccer players (S) and 106 sedentary healthy Italians, as a control group (C). χ2 test was used to look for the difference in genotype distribution of ACTN3, ACE and BDKRB2 between groups. The data were evaluated by forward stepwise multiple regression analysis with the Squat Jump (SJ) and Counter Movement Jump (CMJ) as dependent variables, as well as competition level (CL), ACTN-3, ACE and BDKRB2 genotypes as independent variables. RESULTS: No significant difference was found between groups for ACE, ACTN-3 and BDKRB2 genotype distributions. Forward stepwise multiple regression analysis suggests a significant relationship between a) SJ vs. CL, ACE, and ACTN-3 and b) CMJ vs. CL. For SJ, the multivariate model combining genotypic data and competition level significantly predicted explosive leg-muscle strength in soccer players and variance explained by the function was 23.92%. CONCLUSION: An interaction of two polymorphisms (ACE and ACTN-3) might be able to discriminate quantitative traits crucial for the elite soccer performance, however the contribution of genetic factors to soccer performance is not so high.

Prevalence and trend of overweight and obesity among Sardinian conscripts (Italy) of 1969 and 1998.

This study evaluated the prevalence of overweight and obesity in the male Sardinian population (Italy), and verifies that it has increased over the last 30 years. Data were collected during 2003-2004 from military registers in the Archive of the Military District of Cagliari for the years 1969 and 1998. A total of 22,345 forms were analysed from all Sardinia. The conscripts were classified on the basis of their place of residence and socioeconomic status. The overall prevalence of overweight and obesity in Sardinia were 4.33% and 0.55%, respectively, for the conscripts of 1969 and 9.8% and 3% for 1998. Olbia-Tempio (northern Sardinia) was the province with the highest incidence of overweight and obesity in 1969, and Nuoro (central Sardinia) had the highest incidence in 1998. Distribution of body mass index, overweight and obesity across the island showed a statistically significant heterogeneity that strongly decreased from 1969 to 1998. Among the conscripts of 1969, the incidence of overweight and obesity were higher in rural than in urban regions. An opposite trend was observed for the 1998 prevalence, it being more frequent in urban than rural regions. Comparison with other Italian regions was made. The percentages of overweight and obese individuals in Sardinia have markedly increased during the last 30 years, but their low incidence with respect to other Italian populations could be explained by the genetic peculiarity of the island. The change in the internal distribution of obesity clearly reflects socioeconomic changes.

High frequencies of short alleles of NOS1 (CA)n polymorphism in beta(0)39 carriers from Corsica Island (France).

In this work we investigated about the presence of a correlation between a (CA)n repeat located in exon 29 of NOS1 gene and the beta-thalassemia trait in Corsica Island (France). We genotyped a sample of individuals with beta-thalassemia minor (N=110) and an ethnically matched control (N=113) from Balagna, a region of Corsica Island (France). Results highlighted the high frequencies of allele with 16 and 17 repeats in the thalassemic sample. From these results we suggest, that high frequencies of alleles with 16 and 17 repeats, could be a consequence of past malarial endemicity.

Non-random distribution of 17 Y-chromosome STR loci in different areas of Sardinia.

Allele frequencies of 17 Y-chromosome short tandem repeat (STR) loci, included in the AmpFlSTR® Y-FilerTM amplification kit, were analyzed for the first time in different samplings (N=268) from Sardinia, Italy. Samples were collected from three isolated populations (N=139) and three open populations (N=129). A total of 230 unique haplotypes were detected; the observed haplotype diversity and discrimination capacity were 0.998 and 0.858, respectively. The data presented confirm that Sardinian population is well differentiated from other Italian and Mediterranean populations. Although regarded as a homogeneous population, substantial heterogeneity was detected when Sardinian isolated villages or microareas were analyzed. Our results highlights the importance of building a Sardinia-own database, organized by small areas, as a powerful tool for both forensic applications and population genetics studies.

Human Y-chromosome variation in the western Mediterranean area: implications for the peopling of the region.

Y-chromosome variation was analyzed in a sample of 1127 males from the Western Mediterranean area by surveying 16 biallelic and 4 multiallelic sites. Some populations from Northeastern Europe and the Middle East were also studied for comparison. All Y-chromosome haplotypes were included in a parsimonious genealogic tree consisting of 17 haplogroups, several of which displayed distinct geographic specificities. One of the haplogroups, HG9.2, has some features that are compatible with a spread into Europe from the Near East during the Neolithic period. However, the current distribution of this haplogroup would suggest that the Neolithic gene pool had a major impact in the eastern and central part of the Mediterranean basin, but very limited consequences in Iberia and Northwestern Europe. Two other haplogroups, HG25.2 and HG2.2, were found to have much more restricted geographic distributions. The first most likely originated in the Berbers within the last few thousand years, and allows the detection of gene flow to Iberia and Southern Europe. The latter haplogroup is common only in Sardinia, which confirms the genetic peculiarity and isolation of the Sardinians. Overall, this study demonstrates that the dissection of Y-chromosome variation into haplogroups with a more restricted geographic distribution can reveal important differences even between populations that live at short distances, and provides new clues to their past interactions.

Efficiency of Ber-EP4 antibody for isolating circulating epithelial tumor cells before RT-PCR detection.

We compared the efficacy of 4 methods for isolating circulating tumor cells: immunocapture with Ber-EP4-coated magnetic beads, density gradient separation, ammonium chloride, and distilled water-mediated erythrocyte lysis. Human blood from healthy volunteers was mixed with serial dilutions of prostate (LNCaP) and liver (HepG2) derived tumor cells. Isolation of circulating tumor cells was followed by reverse transcriptase-polymerase chain reaction with primers specific for prostate-specific antigen and alpha-fetoprotein. Ber-EP4 antigen expression was evaluated by immunohistochemistry in 27 hepatocellular carcinomas and 34 prostate adenocarcinomas. Peripheral blood samples from 12 patients with hepatocellular carcinoma and 10 with prostate adenocarcinoma also were tested. Density gradient separation and Ber-EP4 immunocapture were the most sensitive techniques for isolating circulating tumor cells in in vitro tests. Isolation by density gradient separation was significantly more sensitive than Ber-EP4 immunocapture when applied to peripheral blood samples of patients with cancer, a result consistent with the variable expression of Ber-EP4 antigen that we found by immunohistochemistry in prostate adenocarcinomas and hepatocellular carcinomas.

Mitochondrial control-region sequence variation in the Corsican population, France.

The mtDNA sequence variation of the hypervariable segment I of the control region was studied in 47 unrelated individuals of Corsican origin from Corte (Corsica, France). Thirty-one different sequences were identified by 40 variable sites, of which five involve transversions. The nucleotide diversity among the sequences was estimated as 1.03%. The pairwise difference agreed with the model proposed by Rogers and Harpending ([1992] Mol Biol Evol 9:552-569) and appeared bell-shaped, with only one peak at 3.71, indicating the occurrence of a single episode of demographic expansion roughly 14,443 to 41,584 years ago. From our results it seems that the ancestral Corsican population expanded more recently than all other studied European populations. Compared to other populations by genetic distances and a neighbor-joining tree, Corsicans appear most closely linked to the Basques and Sardinians than to other populations. Although the results substantiate an east-to-west migration, some problems are evident: 1) the estimates of demographic expansion are not in agreement with paleontological data; 2) the expansion occurred later than the expansion of the Sardinian population; and 3) the genetic affinity between Corsicans, Basques, and Sardinians. Answers will need to come from archaeological, paleontological, genetic, geological, and climatological observations. Finally, the study of mtDNA confirms what had already been shown with classic genetic markers. Am. J. Hum. Biol. 12:339-351, 2000. Copyright 2000 Wiley-Liss, Inc.

Genetic structure of southwestern Corsica (France).

The distribution of nine red cell enzymes (ACP, ADA, AK, DIA, ESD, GLO1, PGM1, PGD, and SOD) and seven plasma proteins (C3, GC, HP, ORM, PI, PLG, and TF) was analyzed in a sample of 274 unrelated individuals from the southwestern area of Corsica (France), specifically from Ajaccio and nearby villages. The aim of the research was to study the genetic structure of Corsica and to add further to our knowledge about microgeographic variability of polymorphisms in Corsica. The analysis, carried out by genetic distances and R-matrix through 39 alleles of 13 genetic markers, reveals a certain degree of differentiation within Corsica. The results show a genetic heterogeneity between Corsica and other European and Mediterranean populations, although the genetic differences appear to be smaller between Corsicans and Sardinians than among Corsicans and other compiled populations. Am. J. Hum. Biol. 10:567-577, 1998. © 1998 Wiley-Liss, Inc.

[Glycoconjugates of the cecal intestinal epithelium of the chick before and after hatching: histochemical study performed with peroxidase-conjugated lectins]. / I glicoconiugati nell'epitelio dell'intestino cieco del pollo prima e dopo la schiusa: studio istochimico eseguito con lectine coniugate a perossidasi.

A battery of seven different horseradish peroxidase-labelled lectins (PNA, ConA, DBA, SBA, LTA, WGA and UEA I) was used to study the distribution and changes of carbohydrate moieties of glycoconjugates in the caecal epithelium (proximal and distal tracts) of the chick embryo and of the 3 days old chicken. The chief results showed that: 1. The appearance of some sugar residues was earlier observed at the epithelium of the distal tract than the proximal one (Tab. 2). 2. The presence of sialic acid was detected only after hatching (Fig. 4, Tab. 2). 3. During the embryonic caecal development enterocytes and goblet cells were characterized by the presence of the same sugar residues (Tab. 2). 4. By a quantitative point of view, differences in sugar residues content between the epithelium of the proximal and distal tract were observed. The epithelial cells of the distal tract were generally characterized by an higher content of saccharide moieties (Tab. 2). 5. At the end of the incubation period and after hatching enterocytes and goblet cells showed differences in content of some sugar residues (Fig. 1-3, Fig. 5-8, Tab. 2).

Y-chromosome-specific microsatellite variation in a population sample from Sardinia (Italy).

The genetic variability at seven Y-chromosomal microsatellite loci was studied among 113 Sardinian males from the regions of Campidano of Cagliari, Nuorese and Gallura. The allelic and haplotypes frequency distributions are compared between our sample and from the available literature data on Mediterranean and European populations. As a result, the Sardinian samples showed a very high allele frequency in the DYS19*17, a rarity in the rest of Europe, probably due to the founder effect. The analysis has shown an intra-population genetic heterogeneity and genetic differentiation from other Mediterranean and European population deal with. The results reported in this work showed that of the Euro-Mediterranean populations, the Corsican of the South seems to have the most genetic affinity with the Sardinians, thereby reaffirming the observations from previous works that had suggested a certain level of genetic similarity.

HLA phenotype and haplotype frequencies in Sardinia (Italy).

The gene and haplotype frequencies of the HLA-A, B, Cw, DR and DQ loci were determined in two Sardinian samples from the Nuoro (N = 252) and Sassari (N = 153) districts. Our data were compared with those reported for other Italian, European and Mediterranean populations and previously studied Sardinian samples. The results showed that the two samples differ from other Italian and European populations in the frequencies of many alleles and haplotypes. For example in the A2, B18, Cw5 and DR3 allele frequencies and the A1-B8, A2-B17, A3-B7, A30-B18, A2-Cw7, A30-Cw5, A30-DR3, A32-DR2, Cw5-DR3 and Cw7-DR4 haplotype frequencies. In common with the Mediterranean populations, Sardinians, too, have a limited number of haplotypes with significant linkage disequilibrium. The results revealed, therefore, significant genetic differentiation between Sardinians and other European and Mediterranean populations, confirming the genetic peculiarity of the Sardinians.

24 bp duplication of CHIT1 gene is not correlated with coronary artery disease in Corsica Island (France).

In this study we analyzed allele and genotype distributions of 24 bp duplication of the CHIT1 gene in a sample of patients (N=300) with coronary artery disease (CAD) and in a control group (N=300) from central Corsica (France), with the aim to investigate the possible association between CHIT1 genotypes and CAD in Corsican population. Serum chitotriosidase activity is increased in individuals experiencing an ischemic stroke of atherothrombotic etiology and in subjects with ischemic heart disease. Our results suggest that 24 bp duplication of CHIT1 gene is not correlated with CAD in Corsican population, according to a previous study carried out on a Spanish sample. Gene prevalence and perhaps gene-disease associations vary according to ethnicity. Further studies, based on different ethnic groups, could be suitable to determine the implication of this polymorphism with respect to CAD.

Cholesteryl ester transfer protein gene polymorphisms are associated with coronary artery disease in Corsican population (France).

The aim of the present study was to investigate the association between coronary artery disease (CAD) and Cholesterol Ester Transfer Protein (CETP) (gaaa)n polymorphisms of the CETP gene in Central Corsica island (France). The study group was composed by 300 unrelated Corsican patients with angiographically documented CAD and 300 unrelated healthy blood donors. Significant differences were observed in the distribution of CETP (gaaa)n alleles between the groups under study (p=0.03; chi(2): 16.8, df: 8). The occurrence of a long allele (408 bp) was higher in cases (12%) than in control group (2%), showing a 6.75-fold increased risk for CAD in Corsica patients (p=0.0055; OR=6.750; 95% CIs=1.47-31.00). The correlation of this polymorphism with the lipid profile (cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol and triglycerides) in the patients group was determined. There was a significant association of the long alleles of CETP (gaaa)n with HDL-C levels. In the patient and in the control groups the LL genotypes had lower HDL-C compared with the SS and SL genotypes (p<0.0001). In summary our results suggest that the genetic variation at the CETP gene may play an important role in determining CAD in Corsican population.

The ins and outs of population relationships in west-Mediterranean islands: data from autosomal Alu polymorphisms and Alu/STR compound systems.

The islands of the West Mediterranean have played a central role in numerous archaeological, historical and anthropological studies due to their active participation in the history of main Mediterranean civilisations. However, genetic data failed to fit in both their degree of internal differentiation and relationships. A set of 18 Alu markers and three short tandem repeats (STRs) closely linked to the CD4, F13B and DM Alu have been analysed in seven samples from Majorca, Corsica, Sardinia and Sicily to explore some of these issues. Our samples show a high genetic heterogeneity inside and among islands for the Alu data. Global differentiation among islands (F(ST) 2.2%) is slightly higher than that described for Europeans and North Africans. Both the estimated divergence times among samples and the high population heterogeneity revealed by Alu data are compatible with population differences since the first islands' settlement in the Paleolithic period. However, the high within-population diversities and the remarkable homogeneity observed in both STR and Alu/STR haplotype variation indicated that, at least since Neolithic times, gene flow has been acting in west Mediterranean. Genetic drift in west-coast Sardinia and gene flow in west Sicily have contributed to their general differentiation, whereas Corsica, Majorca and east Sicily seem to reflect more recent historical relationships from continental south Europe.

Genetic characterization of the historical Albanian ethnic minority of Calabria (southern Italy).

Three historical ethnic minorities are present in Calabria: Albanians, Greeks, and Occitans. The Albanian ethnic minority is the more populous, having settled in Calabria between the 15th and 17th centuries, and these populations are now located in the provinces of Cosenza and Catanzaro. In the present study the Albanian population structure is analyzed based on the allele frequencies of six classic genetic markers: ACP, GC, PGM1, AK, ADA, and 6PGD. The results show a significant heterogeneity between the Albanian population in Calabria and the population in Molise. Therefore the cultural and reproductive isolation of the Albanian ethnic minority of Calabria is related to a great genetic peculiarity. Moreover, the frequencies of some alleles, particularly those of the PGM*1W31 variant, and the analysis of the R matrix still show the actual peculiar genetic structure of the Albanians of Calabria, although the genetic flow is evident in the decrease of endogamy and in the increase in the degree of mixing.

Beta-globin cluster haplotypes in normal individuals and beta(0)39-thalassemia carriers from Sardinia, Italy.

Seven polymorphic sites in the beta-globin cluster in association with specific thalassemia mutations were analyzed in a sample from Sardinia, Italy. In order to verify previous works carried out on normal samples (beta(A)/beta(A)) and family studies on beta-thalassemia homozygotes individuals, the haplotype frequencies in both normal individuals (beta(A)/beta(A)) and beta(0)39-thalassemia carriers (beta(A)/beta0) were studied. In our work chromosomes carrying beta(0)39 mutation are characterized by a prevalence of haplotype II (- + + - + + +) (52%) relative to haplotype I (+- - - - + +) (29%), in contrast, among chromosomes with beta(A) the frequency of haplotype I is much greater than that of haplotype II. These data confirm what was found by other authors. Nevertheless, our results disagree with those of previous studies of Sardinians, both in frequencies values and in the numbers of haplotypes identified. Population analysis performed with samples carrying the beta-thalassemic mutation highlighted the peculiarity of Sardinians with respect to other Mediterranean populations. The Corsican population is most similar to the Sardinian population, confirming previous analyses performed with both classical markers and mitochondrial and genomic DNA.

Prevalence of genetic risk factors for coronary artery disease in Corsica island (France).

We have investigated the frequencies of seven markers among 100 unrelated individuals with angiographically documented CAD (Coronary Artery Disease) and among 100 unrelated healthy blood donors in the central region of Corsica island (France). The seven polymorphisms analyzed were chosen from six candidate genes involved in (1) Renin-Angiotensin system: Angiotensin converting enzyme (ACE I/D), (2) Lipid metabolism: Cholesterol Ester Transfer Protein gene (CETP TAQ1B), (3) Platelet aggregation: alpha and beta subunits of the platelet GpIIb/GpIIIa integrin complex (GpIIb HPA3 and GpIIIa Pl(A1/A2)), (4) Coagulation fibrinolysis: Plasminogen Activator Tissue (PLAT TPA25 I/D) and Methylenetetrahydrofolate Reductase (MTHFR C677T and A1298C). The samples were genotyped using the polymerase chain reaction followed by restriction enzyme analysis for the RFLPs. No significant difference in allele frequencies between patient and control groups was observed. The occurrence of the MTHFR T677T genotype and of the T677T/A1298A compound genotype is higher in cases (20%) than in the controls (4%). Odds ratio seems to indicate that individuals with the MTHFR T677T genotype and the T677T/A1298A compound genotype had a 6-fold increased risk for developing CAD (ORs = 6; 95% CIs = 1.96-18.28) suggesting a possible association of MTHFR C677T with the risk of CAD in Corsican population.

An unexpected wide population variation of the G1733A polymorphism of the androgen receptor gene: data on the Mediterranean region.

The androgen receptor (AR) has been proposed as a candidate gene for several cancers (breast, prostate, uterine endometrium, colon, and esophagus). Ethnicity is considered an associated risk factor for some of these cancers. Several case-control genetic studies have been focused in samples of the main ethnic groups, but little is known about the distribution of risk polymorphisms in current populations with accurate ethnic and/or geographic origins. The A allele of the G1733A polymorphism of the AR gene has been associated with increased risk of prostate cancer. We provide data from this marker in 12 samples from 7 Mediterranean countries such as Spain, Italy (Sardinia), Greece, Turkey, Morocco, Algeria, and Egypt. A sample from Ivory Coast has also been analyzed. The A allele distribution shows a frequency in the Ivory Coast population (65.17%) that contrasts with the low values found in Northern Mediterraneans (mean average value of 13.98%). North African populations present two-times higher frequencies (average value of 27.19%) than Europeans. The wide population variation range found for the A allele strengthens the potential interest of further screening as a baseline to the design of future preventive and population health programs.