Berbers and Arabs: Tracing the genetic diversity and history of Southern Tunisia through genome wide analysis.

OBJECTIVES: Tunisia has been a crossroads for people from Africa, Europe, and the Middle East since prehistoric times. At present, it is inhabited by two main ethnic groups, Arabs and Berbers, and several minorities. This study aims to advance knowledge regarding their genetic structure using new population samplings and a genome-wide approach. MATERIALS AND METHODS: We investigated genomic variation, estimated ancestry components and dated admixture events in three Berber and two Arab populations from Southern Tunisia, mining a dataset including Middle Eastern, sub-Saharan, and European populations. RESULTS: Differences in the proportion of North African, Arabian, and European ancestries and the varying impact of admixture and isolation determined significant heterogeneity in the genetic structure of Southern Tunisian populations. Admixture time estimates show a multilayer pattern of admixture events, involving both ethno-linguistic groups, which started around the mid XI century and lasted for nearly five centuries. DISCUSSION: Our study provides evidence that the relationships between genetic and cultural diversity of old and new inhabitants of North Africa in southern Tunisia follow different patterns. The Berbers seem to have preserved a significant part of their common genomic heritage despite Islamization, Arab cultural influence, and linguistic diversity. Compared to Morocco and Algeria, southern Tunisian Arabs have retained a higher level of Arabian ancestry. This is more evident in the semi-nomad R'Baya, who have kept their original Bedouin lifestyle, than in the population from Douz, who have undergone multiple events of stratification and admixture.

Iron Age Italic population genetics: the Piceni from Novilara (8th-7th century BC).

BACKGROUND: Archaeological data provide evidence that Italy, during the Iron Age, witnessed the appearance of the first communities with well defined cultural identities. To date, only a few studies report genetic data about these populations and, in particular, the Piceni have never been analysed. AIMS: To provide new data about mitochondrial DNA (mtDNA) variability of an Iron Age Italic population, to understand the contribution of the Piceni in shaping the modern Italian gene pool and to ascertain the kinship between some individuals buried in the same grave within the Novilara necropolis. SUBJECTS AND METHODS: In a first set of 10 individuals from Novilara, we performed deep sequencing of the HVS-I region of the mtDNA, combined with the genotyping of 22 SNPs in the coding region and the analysis of several autosomal markers. RESULTS: The results show a low nucleotide diversity for the inhabitants of Novilara and highlight a genetic affinity of this ancient population with the current inhabitants of central Italy. No family relationship was observed between the individuals analysed here. CONCLUSIONS: This study provides a preliminary characterisation of the mtDNA variability of the Piceni of Novilara, as well as a kinship assessment of two peculiar burials.

Genetic origins of lactase persistence and the spread of pastoralism in Africa.

In humans, the ability to digest lactose, the sugar in milk, declines after weaning because of decreasing levels of the enzyme lactase-phlorizin hydrolase, encoded by LCT. However, some individuals maintain high enzyme amounts and are able to digest lactose into adulthood (i.e., they have the lactase-persistence [LP] trait). It is thought that selection has played a major role in maintaining this genetically determined phenotypic trait in different human populations that practice pastoralism. To identify variants associated with the LP trait and to study its evolutionary history in Africa, we sequenced MCM6 introns 9 and 13 and ~2 kb of the LCT promoter region in 819 individuals from 63 African populations and in 154 non-Africans from nine populations. We also genotyped four microsatellites in an ~198 kb region in a subset of 252 individuals to reconstruct the origin and spread of LP-associated variants in Africa. Additionally, we examined the association between LP and genetic variability at candidate regulatory regions in 513 individuals from eastern Africa. Our analyses confirmed the association between the LP trait and three common variants in intron 13 (C-14010, G-13907, and G-13915). Furthermore, we identified two additional LP-associated SNPs in intron 13 and the promoter region (G-12962 and T-956, respectively). Using neutrality tests based on the allele frequency spectrum and long-range linkage disequilibrium, we detected strong signatures of recent positive selection in eastern African populations and the Fulani from central Africa. In addition, haplotype analysis supported an eastern African origin of the C-14010 LP-associated mutation in southern Africa.

Evaluating mtDNA patterns of genetic isolation using a re-sampling procedure: A case study on Italian populations.

BACKGROUND: A number of studies which have investigated isolation patterns in human populations rely on the analysis of intra- and inter-population genetic statistics of mtDNA polymorphisms. However, this approach makes it difficult to differentiate between the effects of long-term genetic isolation and the random fluctuations of statistics due to reduced sample size. AIM: To overcome the confounding effect of sample size when detecting signatures of genetic isolation. SUBJECTS AND METHODS: A re-sampling based procedure was employed to evaluate reduction in intra-population diversity, departure from surrounding genetic background and demographic stationarity in 34 Italian populations subject to isolation factors. RESULTS: Signatures of genetic isolation were detected for all three statistics in seven populations: Pusteria valley, Sappada, Sauris, Timau settled in the eastern Italian Alps and Cappadocia, Filettino and Vallepietra settled in the Appenines. However, this study was unable to find signals for any of the statistics analysed in 19 populations. Finally, eight populations showing signals of isolation were found for one or two statistics. CONCLUSION: The analysis revealed that the use of population genetic statistics combined with re-sampling procedure can help detect signatures of genetic isolation in human populations, even using a single, although highly informative, locus like mtDNA.

Reevaluating a model of gender-biased gene flow among Sub-Saharan Hunter-gatherers and farmers.

In a previous study, we proposed a model for genetic admixture between African hunter-gatherers and food producers, in which we integrated demographic and genetic aspects together with ethnographic knowledge (Destro-Bisol et al. 2004b). In that study it was possible to test the model only using genetic information from widely dispersed and genetically heterogeneous populations. Here we reevaluate the congruence between the model and patterns of genetic variation using an anthropologically and geographically more homogeneous data set that includes Pygmies and farmers from Cameroon, Congo, and the Central African Republic. As implied by the model, the ratios of mtDNA to Y chromosome Nm estimates (effective population size, N, times the migration rate, m; 0.154 in Pygmies and 6.759 in farmers), support an asymmetric gene flow, with a higher Bantu-to-Pygmy gene flow for paternal than for maternal lineages, and vice versa for farmers. Analyses of intra- and interpopulation genetic variation further support the above observation, showing a prevailing effect of genetic drift on maternal lineages and gene flow on paternal lineages among Pygmies, and an opposite pattern among farmers. We also detected differences between patterns for classical and molecular measures of Y chromosome intrapopulation variation, which likely represent signatures of the introgression of Bantu lineages into the gene pool of Pygmy populations. On the whole, our results seem to reflect differences in the demographic history and the degree of patrilocality and polygyny between the two population groups, thus providing further support to our microevolutionary model in an anthropologically coherent framework.

The genomic echoes of the last Green Sahara on the Fulani and Sahelian people.

The population history of the Sahara/Sahelian belt is understudied, despite previous work highlighting complex dynamics.1,2,3,4,5,6,7 The Sahelian Fulani, i.e., the largest nomadic pastoral population in the world,8 represent an interesting case because they show a non-negligible proportion of an Eurasian genetic component, usually explained by recent admixture with northern Africans.1,2,5,6,7,9,10,11,12 Nevertheless, their origins are largely unknown, although several hypotheses have been proposed, including a possible link to ancient peoples settled in the Sahara during its last humid phase (Green Sahara, 12,000-5,000 years before present [BP]).13,14,15 To shed light about the Fulani ancient genetic roots, we produced 23 high-coverage (30×) whole genomes from Fulani individuals from 8 Sahelian countries, plus 17 samples from other African groups and 3 from Europeans as controls, for a total of 43 new whole genomes. These data have been compared with 814 published modern whole genomes2,16,17,18 and with relevant published ancient sequences (> 1,800 samples).19 These analyses showed some evidence that the non-sub-Saharan genetic ancestry component of the Fulani might have also been shaped by older events,1,5,6 possibly tracing the Fulani origins to unsampled ancient Green Saharan population(s). The joint analysis of modern and ancient samples allowed us to shed light on the genetic ancestry composition of such ancient Saharans, suggesting a similarity with Late Neolithic Moroccans and possibly pointing to a link with the spread of cattle herding. We also identified two different Fulani clusters whose admixture pattern may be informative about the historical Fulani movements and their later involvement in the western African empires.

The peopling of Europe and the cautionary tale of Y chromosome lineage R-M269.

Recently, the debate on the origins of the major European Y chromosome haplogroup R1b1b2-M269 has reignited, and opinion has moved away from Palaeolithic origins to the notion of a younger Neolithic spread of these chromosomes from the Near East. Here, we address this debate by investigating frequency patterns and diversity in the largest collection of R1b1b2-M269 chromosomes yet assembled. Our analysis reveals no geographical trends in diversity, in contradiction to expectation under the Neolithic hypothesis, and suggests an alternative explanation for the apparent cline in diversity recently described. We further investigate the young, STR-based time to the most recent common ancestor estimates proposed so far for R-M269-related lineages and find evidence for an appreciable effect of microsatellite choice on age estimates. As a consequence, the existing data and tools are insufficient to make credible estimates for the age of this haplogroup, and conclusions about the timing of its origin and dispersal should be viewed with a large degree of caution.

When gender matters: new insights into the relationships between social systems and the genetic structure of human populations.

Due to its important effects on the ecological dynamics and the genetic structure of species, biologists have long been interested in gender-biased dispersal, a condition where one gender is more prone to move from the natal site. More recently, this topic has attracted a great attention from human evolutionary geneticists. Considering the close relations between residential rules and social structure, gender-biased dispersal is, in fact, regarded as an important case study concerning the effects of socio-cultural factors on human genetic variation. It all started with the seminal paper by Mark Seielstad, Erich Minch and Luigi Luca Cavalli Sforza from Stanford University (Seielstad et al. 1998). They observed a larger differentiation for Y-chromosome than mitochondrial DNA between extant human populations, purportedly a consequence of the prevalence of long-term patrilocality in human societies. Subsequent studies, however, have highlighted the need to consider geographically close and culturally homogeneous groups, disentangle signals due to different peopling events and obtain unbiased estimates of genetic diversity. In this issue of Molecular Ecology, not only do Marks et al. (2012) adopt an experimental design which addresses these concerns, but they also take a further and important step forward by integrating the genetic analysis of two distant populations, the Basotho and Spanish, with data regarding migration rates and matrimonial distances. Using both empirical evidence and simulations, the authors show that female-biased migration due to patrilocality might shape the genetic structure of human populations only at short ranges and under substantial differences in migration rates between genders. Providing a quantitative framework for future studies of the effects of residential rules on the human genome, this study paves the way for further developments in the field. On a wider perspective, Marks et al.'s work demonstrates the power of approaches which integrate biological, cultural and demographic lines of evidence in the study of relations between social and genetic structures of human populations.

How can we get more open access to medical studies? Simple, let's take the green road.

Open Access (OA) to research publications is a fundamental resource for the advancement of scientific research. To facilitate the transition to OA, publishers and institutions have begun negotiating the so-called transformative agreements, contracts combining access to subscription journals with the ability to publish OA. While the debate on transformative agreements is very much alive, little attention is being paid to the "green road," the practice of openly self-archiving manuscripts that have been accepted by journals but not yet typeset. Here we focus on medical literature, showing how the green road could outperform transformative agreements as a means of increasing the full and free availability of peer-reviewed scientific papers.

From the Alps to the Mediterranean and beyond: genetics, environment, culture and the "impossible beauty" of Italy.

Since prehistoric times, Italy has represented a bridge between peoples, genes and cultures. Its peculiar geographical position explains why: it is located in the center of the Mediterranean Sea, flanked by the Balkans and the Hellenic Peninsula to the east, Iberia to the west and surrounded by North Africa to the south and central Europe to the north. This makes Italy of extraordinary interest for the study of some different aspects of human diversity. Here we overview current knowledge regarding the relationships between the structure of the genetic variation of Italian populations and the geographical, ecological and cultural factors that have characterized their evolutionary history. Human presence in Italian territory is deeply rooted in the past. Lithic artifacts produced by the genus Homo and remains of Homo sapiens are among the earliest to have been found on the continent, as shown by the lithic industry of Pirro Nord (between 1.3 and 1.6 Mya) and the dental remains of the "Grotta del Cavallo" (between 45 and 43 Kya). Genetic and genomic studies relating to existing and extinct human groups have shed light on the migrations from Europe, Africa and Asia that created the ancient layers of the genetic structure of today's Italian populations, especially before the Iron Age. The important role of isolation (genetic and cultural) in shaping genetic structure is clearly visible in the patterns of intra- and inter-population diversity observed among Italian ethno-linguistic minorities that settled on the peninsula and on the major islands until the 19th century. Finally, selective pressures have likely driven the distribution of originally adaptive variants and haplotypes that now confer protection or susceptibility to major diseases such as diabetes and cardiovascular disease (in northern Italy) and tuberculosis and leprosy (in the south). What emerges is a picture where the combined effects of migration, isolation and natural selection generated by the interplay of geography, environment and culture have shaped a complex pattern of human diversity that is unique in Europe and which goes hand in hand with today's rich animal and plant biodiversity. In a nutshell, scientific evidence and cultural heritage paint Italy as a place with extremely diverse environments where distant peoples have met since the deep past, bringing and sharing genes and ideas.

HLA class-I diversity in Cameroon: evidence for a north-south structure of genetic variation and relationships with African populations.

HLA class I diversity (loci A, B and C) was analysed in four populations, two from North Cameroon (Podokwo and Uldeme) and two from South Cameroon (Ewondo and Bamileke). Northern and southern Cameroon populations show a substantial genetic diversity in terms of haplotype sharing and genetic distances, even despite the low percentage of variance due to differences among populations evidenced by analysis of molecular variance. The signals of differentiation among populations are consistent with their linguistic affiliation, and support previous evidence, based on autosomal microsatellites and protein loci, which has shown that the complex pattern of genetic variation of Cameroon can in part be described by contrasting the northern and southern part of the country. Looking at our results in the more general framework of HLA diversity in sub-Saharan Africa, it turns out that the Podokwo and Uldeme show some genetic links to populations of the southern western branch of the Sahel corridor, while their high frequency of A*02 and C*04 alleles is congruent with previously hypothesised introgression of non-sub-Saharan alleles. On the other hand, signals of shared ancestry between the Bamileke and Ewondo and the Bantu speakers from central and southern Africa were detected.

The emerging complexity of Open Science: assessing Intelligent Data Openness in Genomic Anthropology and Human Genomics.

In recent decades, the scientific community has become aware of the importance of science being effectively open in order to speed up scientific and technological progress. In this context, the achievement of a robust, effective and responsible form of data sharing is now widely acknowledged as a fundamental part of the research process. The production and resolution of human genomic data has steadily increased in recent years, mainly due to technological advances and decreasing costs of DNA genotyping and sequencing. There is, however, a downside to this process due to the huge increase in the complexity of the data and related metadata. This means it is advisable to go beyond traditional forms of sharing analysis, which have focused on data availability only. Here we present a pilot study that aims to complement a survey on the availability of data related to peer-reviewed publications with an analysis of their findability, accessibility, useability and assessability (according to the "intelligent data openness" scheme). Sharing rates in genomic anthropology (73.0%) were found to be higher than human genomics (32.4%), but lower than closely related research fields (from 96.8% to 79.2% for paleogenetics and evolutionary genetics, respectively). We discuss the privacy and methodological issues that could be linked to this finding. Comparisons of sharing rates across a wide range of disciplines has suggested that the idea of human genomics as a forerunner for the open data movement should be questioned. Finally, both in genomic anthropology and human genomics, findability and useability were found to be compliant with the expectations of an intelligent data openness, whereas only a minor part of studies met the need to make the data completely assessable.

Mitochondrial, Y-chromosomal and autosomal variation in Mbenzele Pygmies from the Central African Republic.

In this paper, we carry out a combined analysis of autosomal (ten microsatellites and an Alu insertion), mitochondrial (HVR-1 sequence, 360 nucleotides) and Y-chromosomal (seven microsatellites) variation in the Mbenzele Pygmies from the Central African Republic. This study focuses on two important questions concerning the admixture and origin of African Pygmies. Ethnographic observations suggest a sex-biased gene flow between the Bantus and Pygmies, an issue which could be clarified through genetic analyses may shed light. A study of intrapopulational variation of mtDNA and Y-chromosome produces results in accordance with the hypothesized matrimonial behaviour. In fact, while shared mitochondrial haplotypes belonging to the L1c5 (or L1c1a1 clade) sub-haplogroup provides evidence of a Pygmy-to-Bantu female biased gene flow, a male biased gene flow from Bantu to Pygmies is supported by the distribution of the Y-chromosomes bearing M2 mutation. The second part of our study regards the question of the genetic relationships between Western and Eastern Pygmies. Our results favour the pre-Bantu hypothesis which suggests that the two Pygmy groups separated in ancient times (at least 18,000 years ago), whereas they do not support the recent divergence and differential admixture hypothesis which posits their separation as a consequence of the Bantu expansion (2,000-3,000 years ago).

Ethnic fragmentation and degree of urbanization strongly affect the discrimination power of Y-STR haplotypes in central Sahel.

Y chromosome short tandem repeats (Y-STRs) are commonly used to identify male lineages for investigative and judicial purposes and could represent the only source of male-specific genetic information from unbalanced female-male mixtures. The Yfiler Plus multiplex, which includes twenty conventional and seven rapidly-mutating Y-STRs, represents the most discriminating patrilineal system commercially available to date. Over the past five years, this multiplex has been used to analyze several Eurasian populations, with a reported discrimination capacity (DC) approaching or corresponding to the highest possible value. However, despite the inclusion of rapidly mutating Y-STRs, extensive haplotype sharing was still reported for some African populations due to a number of different factors affecting the effective population size. In the present study, we analyzed 27 Y-STRs included in the Yfiler Plus multiplex and 82 Y-SNPs in central Sahel (northern Cameroon and western Chad), an African region characterized by a strong ethnic fragmentation and linguistic diversity. We evaluated the effects of population sub-structuring on genetic diversity by stratifying a sample composed of 431 males according to their ethnicity (44 different ethnic groups) and urbanization degree (four villages and four towns). Overall, we observed a low discrimination capacity (DC = 0.90), with 71 subjects (16.5 %) sharing 27 Y-STR haplotypes. Haplotype sharing was essentially limited to subjects with the same binary haplogroup, coming from the same location and belonging to the same ethnic group. Haplotype sharing was much higher in rural areas (average DC = 0.83) than urban settlements (average DC = 0.96) with a significant correlation between DC and census size (r = 0.89; p = 0.003). Notably, we found that genetic differentiation between villages from the same country (ΦST = 0.14) largely exceeded that found among countries (ΦST = 0.02). These findings have important implications for the choice of the appropriate reference population database to evaluate the statistical relevance of forensic Y-haplotype matches.

Tracing the distribution and evolution of lactase persistence in Southern Europe through the study of the T(-13910) variant.

We investigated the occurrence and intra-allelic variability of the T(-13910) variant located upstream of the lactase gene in 965 individuals from 20 different locations of Italy and Greece. The T(-13910) frequency ranges from 0.072 (Sardinia) to 0.237 (North-East Italy), with a statistically significant difference between North-East Italians and other Italian populations. The comparison of the lactose tolerance predicted by T(-13910) and that assessed by other studies using physiological tests shows a one-way statistically significant discrepancy that could be due to sampling differences. However, the possible role of other genetic factors underlying lactase persistence is worth exploring. The time of the most recent common ancestor and departures from neutrality of the T(-13910) allele were assessed using three microsatellite loci. Time estimates were found to be congruent with the appearance of dairy farming in Southern Europe and the occurrence of a single introgression event. Robust signals of selection can be observed in North-East Italy only. We discuss the possible role of cultural traits and genetic history in determining these observed micro-evolutionary patterns.

Inter-individual genomic heterogeneity within European population isolates.

A number of studies carried out since the early '70s has investigated the effects of isolation on genetic variation within and among human populations in diverse geographical contexts. However, no extensive analysis has been carried out on the heterogeneity among genomes within isolated populations. This issue is worth exploring since events of recent admixture and/or subdivision could potentially disrupt the genetic homogeneity which is to be expected when isolation is prolonged and constant over time. Here, we analyze literature data relative to 87,815 autosomal single-nucleotide polymorphisms, which were obtained from a total of 28 European populations. Our results challenge the traditional paradigm of population isolates as structured as genetically (and genomically) uniform entities. In fact, focusing on the distribution of variance of intra-population diversity measures across individuals, we show that the inter-individual heterogeneity of isolated populations is at least comparable to the open ones. More in particular, three small and highly inbred isolates (Sappada, Sauris and Timau in Northeastern Italy) were found to be characterized by levels of inter-individual heterogeneity largely exceeding that of all other populations, possibly due to relatively recent events of genetic introgression. Finally, we propose a way to monitor the effects of inter-individual heterogeneity in disease-gene association studies.

The peopling of the last Green Sahara revealed by high-coverage resequencing of trans-Saharan patrilineages.

BACKGROUND: Little is known about the peopling of the Sahara during the Holocene climatic optimum, when the desert was replaced by a fertile environment. RESULTS: In order to investigate the role of the last Green Sahara in the peopling of Africa, we deep-sequence the whole non-repetitive portion of the Y chromosome in 104 males selected as representative of haplogroups which are currently found to the north and to the south of the Sahara. We identify 5,966 mutations, from which we extract 142 informative markers then genotyped in about 8,000 subjects from 145 African, Eurasian and African American populations. We find that the coalescence age of the trans-Saharan haplogroups dates back to the last Green Sahara, while most northern African or sub-Saharan clades expanded locally in the subsequent arid phase. CONCLUSIONS: Our findings suggest that the Green Sahara promoted human movements and demographic expansions, possibly linked to the adoption of pastoralism. Comparing our results with previously reported genome-wide data, we also find evidence for a sex-biased sub-Saharan contribution to northern Africans, suggesting that historical events such as the trans-Saharan slave trade mainly contributed to the mtDNA and autosomal gene pool, whereas the northern African paternal gene pool was mainly shaped by more ancient events.

Complex Ancient Genetic Structure and Cultural Transitions in Southern African Populations.

The characterization of the structure of southern African populations has been the subject of numerous genetic, medical, linguistic, archaeological, and anthropological investigations. Current diversity in the subcontinent is the result of complex events of genetic admixture and cultural contact between early inhabitants and migrants that arrived in the region over the last 2000 years. Here, we analyze 1856 individuals from 91 populations, comprising novel and published genotype data, to characterize the genetic ancestry profiles of 631 individuals from 51 southern African populations. Combining both local ancestry and allele frequency based analyses, we identify a tripartite, ancient, Khoesan-related genetic structure. This structure correlates neither with linguistic affiliation nor subsistence strategy, but with geography, revealing the importance of isolation-by-distance dynamics in the area. Fine-mapping of these components in southern African populations reveals admixture and cultural reversion involving several Khoesan groups, and highlights that Bantu speakers and Coloured individuals have different mixtures of these ancient ancestries.

Overcoming the dichotomy between open and isolated populations using genomic data from a large European dataset.

Human populations are often dichotomized into "isolated" and "open" categories using cultural and/or geographical barriers to gene flow as differential criteria. Although widespread, the use of these alternative categories could obscure further heterogeneity due to inter-population differences in effective size, growth rate, and timing or amount of gene flow. We compared intra and inter-population variation measures combining novel and literature data relative to 87,818 autosomal SNPs in 14 open populations and 10 geographic and/or linguistic European isolates. Patterns of intra-population diversity were found to vary considerably more among isolates, probably due to differential levels of drift and inbreeding. The relatively large effective size estimated for some population isolates challenges the generalized view that they originate from small founding groups. Principal component scores based on measures of intra-population variation of isolated and open populations were found to be distributed along a continuum, with an area of intersection between the two groups. Patterns of inter-population diversity were even closer, as we were able to detect some differences between population groups only for a few multidimensional scaling dimensions. Therefore, different lines of evidence suggest that dichotomizing human populations into open and isolated groups fails to capture the actual relations among their genomic features.

Samples and data accessibility in research biobanks: an explorative survey.

Biobanks, which contain human biological samples and/or data, provide a crucial contribution to the progress of biomedical research. However, the effective and efficient use of biobank resources depends on their accessibility. In fact, making bio-resources promptly accessible to everybody may increase the benefits for society. Furthermore, optimizing their use and ensuring their quality will promote scientific creativity and, in general, contribute to the progress of bio-medical research. Although this has become a rather common belief, several laboratories are still secretive and continue to withhold samples and data. In this study, we conducted a questionnaire-based survey in order to investigate sample and data accessibility in research biobanks operating all over the world. The survey involved a total of 46 biobanks. Most of them gave permission to access their samples (95.7%) and data (85.4%), but free and unconditioned accessibility seemed not to be common practice. The analysis of the guidelines regarding the accessibility to resources of the biobanks that responded to the survey highlights three issues: (i) the request for applicants to explain what they would like to do with the resources requested; (ii) the role of funding, public or private, in the establishment of fruitful collaborations between biobanks and research labs; (iii) the request of co-authorship in order to give access to their data. These results suggest that economic and academic aspects are involved in determining the extent of sample and data sharing stored in biobanks. As a second step of this study, we investigated the reasons behind the high diversity of requirements to access biobank resources. The analysis of informative answers suggested that the different modalities of resource accessibility seem to be largely influenced by both social context and legislation of the countries where the biobanks operate.