Analysis of uniparental markers reveals a complex pattern of migration within Sardinia.

BACKGROUND: From the genetic viewpoint, Sardinia is well differentiated from other surrounding populations. In spite of a common ancestral origin, substantial genetic heterogeneity is observed within the island. Matrimonial pattern, as well as past migration movements, may account for the complex genetic structure of Sardinia. AIM: To compare data from uniparental markers in order to highlight the migration pattern of male and female lineages and check their congruence with the demographic data. SUBJECTS AND METHODS: Genomic DNA was obtained from 279 unrelated males selected from three isolated villages and from three open populations representative of North, Central and South Sardinia. The hypervariable region 1 of mtDNA was sequenced and 17 Y-chromosome loci were genotyped. Parameters of within and among populations diversity were calculated and analysis of migration was performed. RESULTS: When analysed as a whole population, demographic data show a balanced movement of males and females in Sardinia, unlike other Italian and European populations. Remarkably, when the island is divided into geographic areas, different migration patterns are clearly recognisable. Whereas North and Central Sardinia populations show a stronger male migration rate, the South Sardinia population shows a stronger female migration rate. CONCLUSION: Distinct migration patterns of male and female lineages affect the areas investigated differently. These past migration movements are major contributors to the complex genetic structure currently observed in the Sardinian population.

Adipose tissue: another target organ for lead accumulation? A study on Sardinian children (Italy).

OBJECTIVES: This study analyzes the relationship between lead levels and adipose tissue in Sardinian children. As an environmental pollutant, lead occurs in two different chemical forms: inorganic and organic lead; organic lead is present in the environment mainly as lead-alkyls (tetramethyl and tetraethyl lead). The lead-alkyls are characterized by their liposolubility; because of this characteristic, the behavior of organic Pb in the organism is similar to that of persistent organic pollutants (POPs). In fact, the high liposolubility of POPs, synthetic chemical substances highly resistant to biodegradation in both the environment and the human body, gives them a preferential tendency to accumulate in adipose tissue. METHODS: The study sample consisted of 759 children between 11 and 15 years resident in various municipalities of Sardinia. Hair lead levels (PbH) were used as the biomarker of exposure, while several anthropometric indexes were adopted to evaluate the adipose tissue: weight, body mass index, waist circumference, waist to hip circumference ratio, and sum of skinfolds (Σskf). RESULTS: The results of the multivariate ridge regression analysis, controlling for sex and age, show a significant positive relationship between logPbH and logΣskf but not the other adiposity indicators. CONCLUSIONS: This results suggests that organic lead tends to accumulate in adipose tissue, although it would be appropriate to measure lead levels in the adipose tissue itself in order to verify the results. Hence this tissue could be considered a possible new biological matrix for the evaluation of environmental lead exposure.

Microgeographic differentiation in historical Yemen inferred by morphometric distances.

This study analyzed the variations in space of 8 body dimensions and 11 measures of the head of 1,244 adult Yemenite males, collected in 1933/34 by Coon in Yemen and in Hadhramawt. The aim was to evaluate the presence of geographic microdifferentiation of the populations settled in the different regions of Yemen at the time. Coon sub-divided the sample into six geographical areas according to birthplace and ethnicity of the individuals: Tihamah, the Western Mountains, the Central Plateau, the South Coast, the Eastern Mountains, and Hadhramawt. The results of ANCOVA (age as covariate) show that the observed differences of all variables among the six groups were highly statistically significant. Tukey's post-hoc test reveals higher statistically significant differences among four main groups: (1) Tihamah; (2) the Western Mountains and Central Plateau; (3) the Eastern Mountains; and (4) the Southern Coast and Hadhramawt. Multiple discriminant analysis carried out using only the data of the 11 measures of the head, the more "genetically" determined variables, confirmed these differences. Indeed, the first canonical variate well separates the groups with the Tihamah, Southern Coast and Hadhramawt on the one side and the Eastern Mountains, Western Mountains and Central Plateau on the other. The second canonical variate separates the Tihamah, Western Mountains and Central Plateau from the Eastern Mountains, Southern Coast and Hadhramawt. In conclusion, the Yemenite population seems to be composed of three morphologically distinct groups and an Eastern Mountains group which is positioned between the group formed by the Southern Coast and Hadhramawt and the Western Mountains and Central Plateau group. The Tihamah is the most distant from all the other groups. These differences are probably due to the presence/absence of geographical and cultural barriers that have favored/blocked the gene flow over the years. Indeed, the entire coastal bell, through the centuries, has constituted one of the principal commercial routes between the East, Africa, and the eastern Mediterranean, while the high inland mountains have isolated the remaining communities. This data is also confirmed by genetic studies. Finally, the average height (162.6 cm) of the global Yemenite population, compared to data from the other six middle-eastern Arab countries and Egypt, was found to be 3-6 cm less. This characteristic will be further studied, analyzing variations in average height according to the different age classes in order to evaluate any possible secular changes.

Hair lead levels to evaluate the subclinical impact of lead on growth in Sardinian children (Italy).

OBJECTIVES: The aim of this study was to determine if there are significant relationships between lead concentrations in children's hair and height, sitting height, and estimated leg length. METHODS: We analyzed three samples collected at different times: 1998, 2002, 2007. The total sample consisted of 825 children between 11 and 14 years of age living in different municipalities of Sardinia (Italy). Inductively coupled plasma atomic emission spectrometry (1998), inductively coupled plasma atomic absorption spectrometry (2002), and inductively coupled mass spectrometry (2007) were used to measure the lead concentration in hair (PbH). Some AAS measurements were also performed on the 1998 and 2007 samples to check the reliability of the data. RESULTS: The mean PbH is much higher in 1998 (5.84 µg/g) than in 2002 (1.49 µg/g) and 2007 (0.78 µg/g). Multivariate regression analysis of the three samples, controlling for age and sex, indicates a subclinical impact of lead on growth that differs according to the mean lead concentration in the hair. In fact, for 1998, the relationships between all three anthropometric variables and logPbH are significantly negative. For 2002, there are significant negative associations between height and estimated leg length and logPbH but not between sitting height and logPbH. For 2007, there are not significant associations between logPbH and anthropometric variables. CONCLUSIONS: Our results support the use of hair lead levels as a biomarker to assess the impact of subclinical lead on the physical growth of children, especially when the study area presents medium and/or high levels of lead pollution.

Seasonality of marriages in sardinian pastoral and agricultural communities in the nineteenth century.

The study of marriage seasonality of populations with different socioeconomic backgrounds may contribute to the better understanding their reproductive behaviours. This study analyses the monthly distribution of marriages in the 19th century in four agricultural villages and four pastoral villages on the island of Sardinia (Italy). The data were derived from 7340 marriage acts (3571 for the four agricultural villages and 3769 for the four pastoral villages). The aim is to ascertain whether the Sardinian agricultural and pastoral communities followed the matrimonial models reported for contemporary Italy and Europe and whether there was a change in the monthly distribution of marriages between the two halves of the 19th century. The results suggest that the marriage seasonality of the Sardinian farmers and shepherds was very similar to the patterns shown in the 19th century by Italian and European agricultural and pastoral communities. The Sardinian farmers preferred to marry in autumn-winter, while the Sardinian shepherds had a very high concentration of marriages in summer-autumn. Both communities avoided marriages in the Advent and Easter periods and in the month of May (dedicated to the Virgin Mary), and the farmers also in August (also dedicated to the Virgin Mary). Despite a certain seasonal stability, there was a significant change in the monthly distribution of marriages between the two halves of the 19th century in both the agricultural and pastoral communities, probably due to a series of laws that transformed the centuries-old socioeconomic system of Sardinia in the second half of the century.

Town and gender effects on hair lead levels in children from three Sardinian towns (Italy) with different environmental backgrounds.

This study reports hair lead (PbH) levels measured in 2002 in 193 children from three Sardinian towns: Carbonia, Gonnesa, and Sinnai. Carbonia and Gonnesa are in a polluted area of Sardinia due to their vicinity to the industrial zone of Portovesme. As a consequence of its economy and location, Sinnai is not exposed to lead pollution. PbH concentrations were determined by inductively coupled plasma atomic absorption spectrometry. The aim of this study was to evaluate if hair is a reliable biomarker to determine different degrees of exposure of populations to lead pollution and if there is a tendency to higher accumulation by males or females. The girls of Carbonia had the highest mean PbH value (2.21 microg/g), followed by the Gonnesa girls (2.03 microg/g), Carbonia boys (1.86 microg/g), Gonnesa boys (0.91 microg/g), and finally the Sinnai boys (0.68 microg/g) and girls (0.50 microg/g). Two-way analysis of covariance, with age as covariate, revealed a significant effect of town and sex on log PbH. Spearman's rank correlation coefficient indicated a significant positive concordance between PbH levels and gender (score for males=1, females=2). The results suggest that hair is a reliable biomarker to determine different levels of exposure of populations to lead pollution, and they indicate that females tend to accumulate lead in the hair more than males of the same age.

Geographical and temporal changes of anthropometric traits in historical Yemen.

This study investigates secular changes of anthropometric variables among four geographic groups in historical Yemen, to evaluate possible regional differences in the evolution of living standards. Nineteen somatic and cephalic measures collected by Coon in 1939, and 8 anthropometric indices in 1244 Yemenite adult males were analyzed. The individuals were divided into 10-year age groups. Within-group variations were tested by One-way ANCOVA (age as covariate). ANCOVA (controlling for age), and Forward stepwise discriminant analysis were used to evaluate and represent regional differences. ANCOVA and discriminant analysis confirmed and enhanced previous findings. At the time, the Yemenite population presented high intergroup heterogeneity. The highest mean values of height at all ages were found in the "mountain" region, which is characterized by very fertile soils and where, nowadays, most of the cereals and pulses are grown and where most livestock is raised. Within-group variations were limited and generally inconsistent in all geographic regions and concern vertical dimensions, but mean values of height never differed. The prolonged internal isolation of these groups resulted in significant regional morphometric differentiation. The main evidence comes from height which suggests that socioeconomic factors have played a role. Nevertheless, the possible better living conditions experienced by the "mountain" group, with the highest mean values of stature in all periods, did not allow the secular trend to take place in that region, too.

When data sharing gets close to 100%: what human paleogenetics can teach the open science movement.

This study analyzes data sharing regarding mitochondrial, Y chromosomal and autosomal polymorphisms in a total of 162 papers on ancient human DNA published between 1988 and 2013. The estimated sharing rate was not far from totality (97.6% ± 2.1%) and substantially higher than observed in other fields of genetic research (evolutionary, medical and forensic genetics). Both a questionnaire-based survey and the examination of Journals' editorial policies suggest that this high sharing rate cannot be simply explained by the need to comply with stakeholders requests. Most data were made available through body text, but the use of primary databases increased in coincidence with the introduction of complete mitochondrial and next-generation sequencing methods. Our study highlights three important aspects. First, our results imply that researchers' awareness of the importance of openness and transparency for scientific progress may complement stakeholders' policies in achieving very high sharing rates. Second, widespread data sharing does not necessarily coincide with a prevalent use of practices which maximize data findability, accessibility, useability and preservation. A detailed look at the different ways in which data are released can be very useful to detect failures to adopt the best sharing modalities and understand how to correct them. Third and finally, the case of human paleogenetics tells us that a widespread awareness of the importance of Open Science may be important to build reliable scientific practices even in the presence of complex experimental challenges.

Anthropometric changes in urban Sardinian children 7 to 10 years between 1975-1976 and 1996.

This study is a comparison of several anthropometric variables in school children of the same age (7-10 years) and sex measured in two primary schools in Cagliari (Sardinia, Italy) at an interval of 20 years (1996 vs. 1975-1976). For both males and females of each age-class, there are significant differences in the following dimensions: weight, stature, estimated lower limb length, biacromial breadth, xiphoid chest circumference, xiphoid chest depth, and bicristal breadth, and also in relative sitting height, cephalic index, and facial index. The means of the relative sitting height, cephalic, and facial indexes are higher in the children measured in 1975-1976 than in those measured in 1996. There are no significant differences in sitting height and arm length. In addition, the estimated BMIs of the 1975-1976 sample are, on average, lower than those of the 1996 sample. The results suggest that urban Sardinian children sampled in 1996 are generally taller, heavier, and larger and have a longer head and wider face than their peers of 20 years earlier. The increase in stature is due more to an increase in lower limb length than in sitting height. Am J. Hum. Biol. 12:782-791, 2000. Copyright 2000 Wiley-Liss, Inc.

Linguistic, geographic and genetic isolation: a collaborative study of Italian populations.

The animal and plant biodiversity of the Italian territory is known to be one of the richest in the Mediterranean basin and Europe as a whole, but does the genetic diversity of extant human populations show a comparable pattern? According to a number of studies, the genetic structure of Italian populations retains the signatures of complex peopling processes which took place from the Paleolithic to modern era. Although the observed patterns highlight a remarkable degree of genetic heterogeneity, they do not, however, take into account an important source of variation. In fact, Italy is home to numerous ethnolinguistic minorities which have yet to be studied systematically. Due to their difference in geographical origin and demographic history, such groups not only signal the cultural and social diversity of our country, but they are also potential contributors to its bio-anthropological heterogeneity. To fill this gap, research groups from four Italian Universities (Bologna, Cagliari, Pisa and Roma Sapienza) started a collaborative study in 2007, which was funded by the Italian Ministry of Education, University and Research and received partial support by the Istituto Italiano di Antropologia. In this paper, we present an account of the results obtained in the course of this initiative. Four case-studies relative to linguistic minorities from the Eastern Alps, Sardinia, Apennines and Southern Italy are first described and discussed, focusing on their micro-evolutionary and anthropological implications. Thereafter, we present the results of a systematic analysis of the relations between linguistic, geographic and genetic isolation. Integrating the data obtained in the course of the long-term study with literature and unpublished results on Italian populations, we show that a combination of linguistic and geographic factors is probably responsible for the presence of the most robust signatures of genetic isolation. Finally, we evaluate the magnitude of the diversity of Italian populations in the European context. The human genetic diversity of our country was found to be greater than observed throughout the continent at short (0-200 km) and intermediate (700-800km) distances, and accounted for most of the highest values of genetic distances observed at all geographic ranges. Interestingly, an important contribution to this pattern comes from the "linguistic islands"( e.g. German speaking groups of Sappada and Luserna from the Eastern Italian Alps), further proof of the importance of considering social and cultural factors when studying human genetic variation.

Growth charts of head length and breadth for regional areas? A study in Sardinia (Italy).

There exist few standards of head length and breadth from childhood to adulthood in Europoid populations. Moreover, such standards are based on samples that cannot be used as references for all populations since they were taken from different ethnic groups and from different periods. The aims of this study were: (1) to test whether standards derived from North Americans of European extraction can be used to assess the Sardinian population; and (2) to produce growth charts for head length and breadth for Sardinian males and females from 3 to 22 years of age. The cross sectional sample consisted of 9,721 subjects of Sardinian origin (4,884 males and 4,837 females), aged 3-22 years, measured from 1998 to 2008. Growth percentiles were produced with the LMS method. The mean values for each sex in each age class (3-18 years) are almost always significantly lower for both head length and breadth than the corresponding North American values. The exceptions are the head length of boys of 14 years and girls of 16-18 years where values for Sardinians are lower, but not significantly so. The results show that the North American standards are not appropriate for the assessment of Sardinian children. For the Sardinian population, specific regional growth charts should be used to correctly evaluate the normal range and the cut-off points of the extreme percentiles.

Mine, yours, ours? Sharing data on human genetic variation.

The achievement of a robust, effective and responsible form of data sharing is currently regarded as a priority for biological and bio-medical research. Empirical evaluations of data sharing may be regarded as an indispensable first step in the identification of critical aspects and the development of strategies aimed at increasing availability of research data for the scientific community as a whole. Research concerning human genetic variation represents a potential forerunner in the establishment of widespread sharing of primary datasets. However, no specific analysis has been conducted to date in order to ascertain whether the sharing of primary datasets is common-practice in this research field. To this aim, we analyzed a total of 543 mitochondrial and Y chromosomal datasets reported in 508 papers indexed in the Pubmed database from 2008 to 2011. A substantial portion of datasets (21.9%) was found to have been withheld, while neither strong editorial policies nor high impact factor proved to be effective in increasing the sharing rate beyond the current figure of 80.5%. Disaggregating datasets for research fields, we could observe a substantially lower sharing in medical than evolutionary and forensic genetics, more evident for whole mtDNA sequences (15.0% vs 99.6%). The low rate of positive responses to e-mail requests sent to corresponding authors of withheld datasets (28.6%) suggests that sharing should be regarded as a prerequisite for final paper acceptance, while making authors deposit their results in open online databases which provide data quality control seems to provide the best-practice standard. Finally, we estimated that 29.8% to 32.9% of total resources are used to generate withheld datasets, implying that an important portion of research funding does not produce shared knowledge. By making the scientific community and the public aware of this important aspect, we may help popularize a more effective culture of data sharing.

Evaluation of association between biomarkers of lead exposure in Sardinian children (Italy).

The aim of this work is to verify whether there are statistically significant correlations between the concentrations of lead in blood, urine, and hair in children. The sample collected in 2007 consists of 163 children of both sexes from 11-14-year-olds, living in three municipalities of Sardinia (Italy). Inductively coupled plasma atomic mass spectrometry has been used in the determination of lead concentration in biological material. For the overall sample, there is a non-significant partial correlation among the three matrices. However, for subjects with blood lead levels ≥5 µg/dL, there is a significant positive partial correlation between the lead levels in blood and hair, but not between blood and urine or between urine and hair. The results suggest that blood is the preferred biomarker to ascertain lead exposure in human populations, whereas hair can be used as a tool screening when an area is exposed to medium or high lead pollution.

Morphometric distances among five ethnic groups and evaluation of the secular trend in historical Libya.

This study analysed the variations, both in space and time, of 10 body dimensions and 2 anthropometric indexes of 745 adult males belonging to 5 ethnic groups of historical Lybia (el-Haràbi, el-Baraghìts, Marabtìn, Oases inhabitants and Tuareg). The data were collected in the years 1928 and 1932 by Puccioni and Cipriani, two Italian anthropologists. The aim was to reconstruct the biological history of Libya at the time, and thus contribute to the ongoing debate on the evolution of the biological standard of living in developing Countries. The subjects were analysed by ethnicity and by 10-year age groups, after adjusting for age. The results of ANCOVA and Tukey's post-hoc test show that among and between groups there are statistical significant differences overall for armspan, height, head breadth, bizygomatic breadth, biiliac breadth/height and head breadth/head length indexes. By means of the cluster analysis, the el-Haràbi, el-Baraghìts and Marabtìn groups cluster together, whereas the Tuareg and Oases inhabitants cluster separately one from the other and both from the other three ethnic groups. Within-group variations are not very marked in all ethnicities. In general, there is the tendency, not statistically significant, to the reduction and/or stasis of body dimensions from the older to the younger, and the differences are greater among the older than the younger age classes. In conclusion, it can be argued that these groups, all different culturally and geographically, were following the same tendency of stasis of the secular trend of the body dimensions considered in this study, and such stasis persisted since, at least, the last twenty years of the 19th century, when the older were born.

Are changes in body dimensions of adult females from Italy (Sardinia and Latium) related to secular trend?

This paper presents secular changes in height, weight, sitting height, relative sitting height, BMI and estimated lower limb length in two samples of Italian adult females from Sardinia (Cagliari) and Latium (Rieti). The samples consist of 579 healthy women from the province of Cagliari and 138 from the town of Rieti, aged 20.0-39.9 years, measured in the period 2003-2006. The women were divided into four 5-year age groups. The anthropometric variables were considered according to different socioeconomic status (SES) in the Cagliari sample, while the Rieti sample was considered as a whole, as the SES was homogeneous. ANOVA results suggest that the secular trend was very slow or had come to a halt in the Rieti sample but continues in the Cagliari sample, as shown by the statistically significant differences for estimated lower limb length (p

Secular changes in human biological variables in Western countries: an updated review and synthesis.

This paper provides a review of the recent literature on some aspects of secular trends in Western countries. In particular, we discuss height variation, mainly on the basis of conscript data. There are still large height differences between European countries, and there is a marked trend for the tallest conscripts to be in northern Europe and the shortest ones in the southern part of the continent. The secular trend in adult height has come to a halt in northern Europe and Italy, while it is still in progress in Belgium, Spain and Portugal. The secular trend in height mainly depends on the increase of lower limb length. Obesity is now epidemic in Western countries, the USA population being the most affected. There is also a progressive anticipation of all the signs of puberty, namely age at menarche, appearance and development of the breasts, genitals and pubic and axillary hair, although there is ethnic/population variability in this regard. A tendency to later onset of menopause has also been recorded. Regarding secular trends in sport, there has been a progressive selection of athletes with larger body dimensions. Finally, the authors provide suggestions for future fruitful directions of the research of the secular trend in human biology.

Italian isolates today: geographic and linguistic factors shaping human biodiversity.

We briefly review the current status of anthropological and genetic studies of isolated populations and of their micro-evolutionary and biomedical applications, with particular emphasis on European populations. Thereafter, we describe the ongoing collaborative research project "Isolating the Isolates: geographic and cultural factors of human genetic variation" regarding Italian extant geographical and/or linguistic isolates, aimed at overcoming the limitations of previous studies regarding geographical coverage of isolates, number and type of genetic polymorphisms under study and suitability of the experimental design to investigate gene-culture coevolutionary processes. An interdisciplinary sampling approach will make it possible to collect several linguistic isolates and their geographic neighbours from Trentino, Veneto, Friuli, Tuscany, Sardinia and Calabria. This will be coupled with a shared genotyping strategy based on mitochondrial and Y-chromosomal polymorphisms. The results will be analyzed with a focus on the role of geographical and cultural factors in shaping human biodiversity. The aims of the project go beyond the simple reconstruction of the genetic structure and history of the examined groups. In fact, the study will also include an assessment for future bio-medical studies and the development of genetic and bio-demographic databases. Ethical and educational aspects are also foreseen by the project, by using informed consents together with disseminating activities in loco, completed by the creation of a dedicated web site for both scientific and public audiences.