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Retrotransposon movements are considered to be an important factor in evolutionary processes and speciation as well as a source of genetic variation. In order to analyze genetic diversity and population structure in Tunisian pistachio species, nine inter-retrotransposon amplified polymorphism (IRAP) markers were used. As a result, eighty-six amplicons were produced among which 98.15 % were polymorphic. Mean numbers of the effective number of alleles (Ne), Shannon’s information index (I) and Nei’s genetic diversity (H) were respectively 1.529, 0.478, and 0.310. The average within-population genetic diversity (Hs) was 0.24 and the total diversity (Ht) was 0.3. The Tunisian pistachio populations exhibited high genetic differentiation (Gst =0.275) and gene flow (Nm = 1.888). The Analysis of Molecular Variance (AMOVA) indicated that variation was very high within populations (83 %). Phylogenetic tree using neighbor- joining (NJ) method and Principal Coordinates Analysis (PCoA) depicted that groupings of Tunisian varieties were made independently of the sex of the trees, but depending on their geographical origin and their breeding status. The modelbased Bayesian clustering (STRUCTURE) confirmed these observations. The inter-retrotransposons amplification polymorphism markers were significantly informative at the interspecific level. Findings reported in our study will be essential toward breeding for new pistachio genotypes with developed chemical and horticultural features.

This investigation aims at assessing patterns of spatial genetic structure of the teleost fish Sardina pilchardus across the Siculo-Tunisian Strait (a well-known discontinuous biogeographic area) a...

The aim of this paper was to determine how the pistachio trees evolve, and the evolving factors that influence pistachio population establishment. For that, we investigated pistachio genetic structure from some regions of Tunisia, by sequencing two noncoding chloroplastic regions (trnL (UAA) and trnL-trnF intergenic spacer). We found strong genetic diversity among groups, with the absence of high differentiation between population pairs. A deep phylogeographical break separated two major clusters: "El-Guetar and "Gafsa/Sidi-Bouzid. This conclusion is proved by the haplotype networks, the phylogenetic trees, and the molecular variance analysis. Different interpretations were proposed to explain this cytoplasm dimorphism, based on the molecular evolution and demographic history analysis: (1) the domestication events, which are very important to understand the variability between the prospective areas, (2) the gene flow between them, a process that occurs both in time and in space through pollen and seeds, and strongly interacts with the local farming systems, (3) the geographical barriers that exist, which limit gene flow transfer and make particular climatic conditions of the El-Guetar oasis. Given that, the genetic diversity study within Tunisian pistachio cultivars is very useful to contribute to the national management effort for the improvement and conservation of pistachio genetic resources. Moreover, in 2017, Tunisia ranked among the top 10 countries in global pistachio production. Thus, studying the diversity of Tunisian pistachio can make an important impact on global production.

The present study represents the first population structure analysis of the black sea urchin Arbacia lixula across part of its African Mediterranean distribution range, the Tunisian coast. This location is appropriate for the study of biogeographical processes given the presence of a well-known discontinuous biogeographic area (the Siculo-Tunisian Strait). Patterns of morphological and genetic variation in this highly dispersive echinoid species were assessed among its populations from the western and eastern Mediterranean coasts of Tunisia. A total of 109 specimens from six sites were collected and examined for morphometric variability in seven morphometric traits. Concordant results, inferred from CDA analyses, pairwise NPMANOVA comparisons and MDS plot, showed significant inter-population differences in the measured traits among the studied populations. In addition, UPGMA clustering and discriminant/Hotelling analysis enabled the delineation of two morphologically differentiated groups assigned to the western and eastern Mediterranean basins. SIMPER analysis showed that total dry weight and test diameter were major contributors to the morphometric separation between locations and among groups. Despite the extensive morphological variation found in A. lixula, genetic analysis of the mitochondrial COI marker recovered only a single evolutionary lineage and showed a lack of population structure as inferred from the results of one-level AMOVA and pairwise comparisons of genetic differentiation. Possible explanations for this genetic pattern are discussed. Notably, the lack of COI divergence patterns, highlighted by shallow genealogy associated with high haplotype diversity and low nucleotide diversity, together with a recent demographic expansion event retrieved from mismatch distribution and BSP analysis could be considered a residual effect of a recent evolutionary history of the species in the Mediterranean.

The present investigation focuses on population structure analysis of the purple sea urchin Paracentrotus lividus across the African Mediterranean coast, with the main aim of assessing the influence of the Siculo-Tunisian Strait on gene flow disruption in this highly dispersive echinoid species. For this purpose, patterns of morphological and genetic variation were assessed among its populations from the western and eastern Mediterranean coasts. A total of 302 specimens from seven Tunisian sites were collected and examined for morphometric variability at twelve morphometric traits. Concordant results, inferred from CDA (canonical discriminant analyses), pairwise NPMANOVA (non parametric multivariate analysis of variance) comparisons and MDS (multidimensional scaling) plot, unveiled significant inter-population differences in the measured traits among the studied populations. Furthermore, the combined use of the one way ANOSIM (analysis of similarities) and the Discriminant/Hotelling analysis allowed unravelling two morphologically differentiated groups assigned to both western and eastern Mediterranean basins. The SIMPER (similarity percentages) routine analysis showed that total dry weight, test diameter and spine length were major contributors to the morphometric separation between locations and between groups. Pattern of phenotypic divergence discerned in P. lividus across the Siculo-Tunisian Strait is interestingly in congruence with that inferred from the genetic investigation of the purple sea urchin populations from the same region based on the analysis of the mtDNA COI (cytochrome oxidase I) gene in 314 specimens from nineteen locations covering a wider geographic transect, streching westward to the Algerian coast and eastward to the Libyan littoral. The specific haplotypic composition characterizing each Mediterranean basin, as inferred from the minimum spanning network, confirmed the geographic partioning of genetic variation, as revealed by F-statistics and AMOVA (analysis of molecular variance) analyses, yielding significant genetic differentiation between eastern and western Mediterranean populations. The newly detected phylogeographic patterns, observed for the first time in P. lividus throughout the explored distribution range, suggest the involvement of different biotic and abiotic processes in shaping such variation, and provide evidence that a large and geographically exhaustive dataset is necessary to unveil phylogeographic structure within widespread marine species, previously cathegorized as panmictic in part of their distribution range.

Chameleons display high karyological diversity in chromosome number (from 2n = 20 to 62), morphology, heterochromatin distribution and location of specific chromosomal markers, making them unique study models in evolutionary cytogenetics. However, most available cytogenetic data are limited to the description of the chromosome number and morphology. Concerning sex chromosomes, our knowledge is limited to ZZ/ZW and Z1Z1Z2Z2/Z1Z2W systems in the genus Furcifer and the isolation of sex-linked, male-specific, sequences in Chamaeleo calyptratus, but the putative XY chromosomes have still to be identified in Chamaeleo and the conservation of male heterogamety in the genus needs confirmation from other species. In this study we performed a molecular and a cytogenetic analysis on C. chamaeleon, using standard, banding methods and molecular cytogenetics to provide a throughout karyological characterization of the species and to identify and locate the putative XY chromosomes. We confirm that the chromosome formula of the species is 2n = 24, with 12 metacentric macrochromosomes, 12 microchromosomes and NORs on the second chromosome pair. Heterochromatin was detected as weak C-bands on centromeric regions, differently from what was previously reported for C. calyptratus. Fluorescence in situ hybridization (FISH) showed the occurrence of interspersed telomeric signals on most macrochromosomes, suggesting that ancient chromosome fusions may have led to a reduction of the chromosome number. Using a combination of molecular and FISH analyses, we proved that male specific Restriction site-Associated DNA sequences (RADseq) isolated in C. calyptratus are conserved in C. chamaeleon and located the putative XY chromosomes on the second chromosome pair. We also identified different transposable elements in the focal taxa, which are highly interspersed on most chromosome pairs.

We investigate the influence of previously postulated biogeographic barriers in the Mediterranean Sea on the population genetic structure of a highly dispersive and continuously distributed coastal species. In particular, we examine nuclear and mitochondrial genetic variation in the marbled crab, Pachygrapsus marmoratus, across part of the African Mediterranean coast in order to assess the influence of the Siculo-Tunisian Strait on its population genetic structure. Four polymorphic microsatellite loci were genotyped for 110 individuals, collected from eight locations covering parts of the Algerian, Tunisian and Libyan coasts. In addition, mtDNA corresponding to the Cox1 gene was sequenced for 80 samples. The corresponding results show contrasting patterns of genetic differentiation. While mtDNA results revealed a homogeneous haplotype composition in our study area, microsatellite data depicted genetic differentiation among populations, but not associated with any geographic barrier. This pattern, ...

Consumers are well-informed about food additives and it is likely that they prefer natural additives over their synthetic analogues. Antioxidants represent a major class of food preservatives, among which tocopherols stand out as one of the most important examples. Interestingly, these compounds are present in relevant amounts in the mycelia of in vitro cultured mushrooms. Accordingly, the mycelia from Ganoderma lucidum, Pleurotus ostreatus and Pleurotus eryngii were used as alternative sources of tocopherols. These extracts were incorporated into different yogurt formulations, which were further compared among each other and with yogurts containing commercial α-tocopherol (E307), regarding their nutritional parameters, fatty acid profile and antioxidant activity. The proposed approach was validated as an effective functionalization strategy, particularly in the case of the G. lucidum mycelium, which showed the highest antioxidant potential, most likely as a result of its tocopherol profile. Furthermore, yogurts prepared with each mycelium extract allowed maintaining the nutritional properties observed in the “blank” yogurt formulation. The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), L. Barros and J. Barreira contracts. This work is funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®. info:eu-repo/semantics/publishedVersion

The present study reports on population structure analysis of the marbled crab Pachygrapsus marmoratus (Fabricius, 1787) from the Tunisian coast, an appropriate location to study biogeographical processes because of the presence of a well-known discontinuous biogeographic area (the Siculo-Tunisian Strait). Patterns of morphological and genetic variation of this highly dispersive and continuously distributed decapod species were assessed among its geographically close populations which cover almost the entire Tunisian coastline. A total of 386 specimens from nine sites were collected and examined for morphometric variability at 14 morphometric traits. The results of multivariate analyses of linear morphometric traits showed the existence of sexual dimorphism in this species by PERMANOVA (Permutational multivariate analysis of variance). In addition, both CDA (Canonical discriminant analysis) and NPMANOVA (Non parametric MANOVA test) analyses revealed statistically significant differences among the studied locations for both sexes. Overall, the outcome of CDA analysis showed that over 87% of individuals could be assigned correctly to three regional groups in both sexes (North, Center and South). Specifically, SIMPER (Similarity Percentages) analysis showed that carapace length, carapace width and merus length were major contributors to the morphometric separation between populations. The pattern of phenotypic variation suggested by morphometric analyses was found to be highly discordant with that suggested by the analysis of a mitochondrial marker (cytochrome oxidase I, COI). Indeed, the results inferred from restriction fragment analysis of the COI in 180 crabs, suggested high genetic homogeneity. Very low levels of haplotype diversity (h) were found in almost all the studied populations, associated with non significant genetic distances for nearly all population comparisons. Explanations to these morphometric and mtDNA patterns as well as the discrepancy between them are discussed.

In the present study, we assessed patterns of morphological variation among populations of the Mediterranean green crabCarcinus aestuariiNardo, 1847 from the Tunisian coast. Eleven morphometric traits were measured on 464 specimens from nine sites, and the pattern of morphological variation among sites was assessed using multivariate approach. Non-parametric MANOVA (NPMANOVA) and non-metric Multidimensional Scaling (MDS) analyses revealed statistically significant differences among the studied locations for both sexes proving that natural variability of the measured traits differs clearly between locations. Canonical discriminant analysis (CDA), on the other hand, showed that over 36% of individuals could be assigned to their location of origin on the basis of their morphology. Correct assignment of individuals to their location was much higher (over 63%) when sites were combined into three regional groups and marked morphological differentiation was found in both sexes. A positive correlation was noted between the squared Mahalanobis distances () and the geographic distances for both male and female green crab populations suggesting isolation by distance. The results obtained indicate that morphological divergence among populations of the green crab can occur over shorter distances than expected based on dispersal potential. Possible drivers of the observed pattern of morphological variation are discussed.

In this study we analysed mitochondrial DNA variation in Penaeus kerathurus prawns collected from seven locations along a transect across the Siculo-Tunisian region in order to verify if any population structuring exists over a limited geographical scale and to delineate the putative transition zone with sufficient accuracy. Partial DNA sequences of COI and 16S genes were analysed. In contrast to the highly conservative 16S gene, the COI sequences exhibited sufficient diversity for population analysis. The COI gene revealed low levels of haplotype and nucleotide diversities. The size of the annual landings of this commercial species suggests large population sizes. Hence, the low genetic diversity detected in this study could indicate a possible reduction in effective population sizes in the past. We detected significant genetic differentiation between eastern and western populations likely due to restricted gene flow across the Siculo-Tunisian boundary. We discuss the different evolutionary forces that may have shaped the genetic variation and suggest that the genetic divide is probably maintained by present-day dispersal limitation.

Understanding the dispersal pattern and mechanisms affecting the mixing of Endan- gered loggerhead sea turtles Caretta caretta is a key issue for establishing sound conservation strategies. Loggerhead turtles are commonly encountered all along the Tunisian coast and partic- ularly in the Gulf of Gabes, which is one of the most important foraging habitats for this species in the Mediterranean Sea. We conducted extensive sampling of 175 juvenile and adult loggerhead turtles that were stranded or incidentally captured in the areas along the northern (NTC), eastern (Gulf of Hammamet, GHAM) and southern (Gulf of Gabes, GGAB) Tunisian coast over a 6 yr period (2004 to 2009). A 380 bp fragment of the mitochondrial DNA control region was sequenced and analysed. Seven haplotypes were revealed, and a gradual variation in haplotype frequencies was observed among the studied areas. The extreme samples (NTC and GGAB) differed geneti- cally from each other, while both were similar to the central sample (GHAM). This finding was confirmed by mixed stock analysis estimates, which suggested that the proportions of Atlantic tur- tles were very high in the NTC and decreased southward, while the proportions of Mediterranean contributions were higher in the GGAB and decreased in the opposite direction. The observed pattern of genetic variation and turtle distribution, which is probably related to differences in geo- morphology and sea surface currents among these coastal areas, should be considered in future management plans.

Specific genetic conditions are known to be associated with high risk of venous thromboembolism. This genetic basis varies widely between ethnic groups. We investigated the distribution of four inherited polymorphisms in 113 unselected Tunisian blood donors by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The allele frequencies of Factor V Leiden (FVL), prothrombin 20210G>A, methylenetetrahydrofolate reductase (MTHFR) 677C>T, and MTHFR 1298A>C mutations were 3, 0.9, 30, and 31%, respectively. The MTHFR 677C>T polymorphism was influenced by age. Twenty-nine of the 113 blood donors demonstrated more than one genetic markers. Hyperhomocysteinemia was found in 12 subjects, and it was statistically associated to the MTHFR 677TT genotype. Principal component analysis allowed disclosing the resemblance between Mediterranean populations. Our findings may be helpful for population genetics study, and provide epidemiologic database for further studies in thrombosis field among Tunisians.

This study reports on the polymorphism of 15 allozyme loci in Ruditapes decussatus clams collected from 11 locations along the Tunisian coasts. We concentrated our sampling effort around the Siculo-Tunisian region to verify if any population structuring exists in this region and to identify the factors that have shaped this structure. Measurements of genetic diversity were quantified both within and between populations, and the geographic variability of gene frequencies was analyzed. Our study shows that the Siculo-Tunisian Strait is an important genetic boundary between eastern and western regions, which agrees with findings for a variety of other species. We suggest that vicariance is a predominant factor shaping the current distribution of genetic diversity of R. decussatus, and the mixing of divergent gene pools from the eastern and western regions still seems to be limited by some physical and/or biological factors.

Surveys of allozyme polymorphisms in the carpet shell clam Ruditapes decussatus have revealed sharp genetic differentiation of populations. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial genes. A partial sequence of a mitochondrial COI gene and of the internal transcribed spacer region (ITS-1) were used to study haplotype distribution, the pattern of gene flow, and population genetic structure of R. decussatus. The samples were collected from twelve populations from the eastern and western Mediterranean coasts of Tunisia, one from Concarneau and one from Thau. A total of twenty and twenty-one haplotypes were detected in the examined COI and ITS1 regions respectively. The study revealed higher levels of genetic diversity for ITS1 compared to COI. The analysis of haplotype frequency distribution and molecular variation indicated that the majority of the genetic variation was distributed within populations (93% and 86% for COI and ITS1 respectively). No significant differentiation was found among eastern and western groups on either side of the Siculo-Tunisian strait. However, distinct and significant clinal changes in haplotypes frequencies between eastern and western samples were found at the most frequent COI haplotype and at three out of five major ITS1 haplotypes. These results suggest the relative importance of historical processes and contemporary hydrodynamic features on the observed patterns of genetic structure.

A fragment of the mitochondrial (mt) 16S ribosomal RNA gene was amplified by PCR and sequenced from individual adult scorpions of the genus Androctonus, which were sampled from central and southern Tunisia and identified using an explicit set of morphological characters. Phylogenetic analyses placed the mtDNA haplotypes in three well-supported monophyletic lineages, corresponding to the morphospecies Androctonusaeneas, Androctonusamoreuxi and Androctonusaustralis. The latter species was the most abundant and widespread, and it was characterized by two mtDNA sub-lineages each of which predominated only north or south of the Chott el Jerid, a seasonally flooded saline depression that divides non-Mediterranean Tunisia. The divergence of the two mtDNA lineages was dated by mtDNA molecular clocks, indicating that the formation of the Chott el Jerid is unlikely to have been the barrier generating the vicariant evolution of the two lineages of A. australis, although it may have impeded their mixing following secondary contact. Both regional mtDNA lineages were found in A. australis hector and A. australisgarzonii, indicating that these two morphological forms are neither monophyletic nor geographically isolated and, therefore, should not be treated as species or subspecies. It is recommended that no subspecies of A. australis should be recognized in North Africa and toxicologists should cease the taxonomic error of referring to a species "Androctonus australis Hector". The morphological form "hector" has no proven association with an increased risk of scorpionism compared with "garzonii". However, it might be prudent to produce anti-venom in Tunisia by using both morphological forms of A. australis collected each side of the Chott el Jerid, because of the evidence for regional variation in toxins. The highest risk for scorpion stings occurs in the central region, where the new diagnostic markers should be used to discover any association between Androctonus species and scorpionism.

The Mugilidae family is an important fish group representing a major source for fisheries and aquaculture. In the south Mediterranean bank, no data are available on this fauna, except for some morphological studies on Tunisian samples. In this study, 16 allozymic loci were used to investigate the phylogenetic relationships within Tunisian mugilids. The results obtained from Hergla lagoon samples highlight five operational taxonomic unit corresponding to the well-known species (Liza aurata, Liza ramada, Liza saliens, Chelon labrosus, Mugil cephalus). Several loci appeared to be diagnostic of these species, but in contrast to Greek mugilid samples, we did not find any diagnostic locus fixed differently for the five species. These results can help aquaculture units to identify accurately the mullet species they subsequently use for stocking aquaculture ponds and inland waters. However, species identity represents very important information, as each species has a different growth rate and salinity tolerance. On the other hand, when compared with North Mediterranean Mugilidae analysed until now, Tunisian samples show a genetic differentiation that could be related to different physicochemical conditions between the North and South banks, similar to those recorded in the eastern and western two Mediterranean basins separated by the Siculo-Tunisian strait. In addition, this study confirms the morphological taxonomy, except for the subdivision of the Liza genus into two sub-genera. The phylogenetic tree is in agreement with that on Languedoc Mugilidae samples (France), indicating that the subdivision of the Liza genus into two sub-genera appears to be without any genetic base.

Ten populations of Penaeus kerathurus (Forskal), a prawn of high commercial value, were sampled from the eastern and western Mediterranean coastal waters of Tunisia and screened electrophoretically for genetic variation at 13 allozyme loci. Four among the six polymorphic loci were out of Hardy–Weinberg equilibrium (H–WE) in at least one population. In the same way, the multilocus test showed deviation from H–WE in six populations. These populations showed heterozygote deficiency whereas the average heterozygosity for the four remaining ones is quite similar to the expected levels. Genetic variability was low. The number of alleles per locus ranged from 1.2 to 1.5 (average=1.3), and the observed heterozygosity varied between 0.010 and 0.048 (average=0.021). Significant population differentiation (FST=0.076, P 0.05). Our data suggest a population structure consistent with separation by Mediterranean Sea basins that might reflect different local biogeographical zones.

We present the results of a chromosomal study (C-, Ag-NOR-, endonuclease digestion, DAPI and CMA(3) banding) carried out on four Tunisian species of amphibians: Bufo mauritanicus, B. viridis, Rana saharica and Discoglossus pictus auritus. For comparative purposes, our cytogenetic analysis was also extended to Moroccan specimens of B. mauritanicus and D. pictus scovazzi. Tunisian specimens of B. viridis display chromosome and chromatin characters very similar to those found in other specimens, both North African and Euro-Asian. By contrast, chromosomes of Tunisian specimens of B. mauritanicus differed from the Moroccan specimens in presenting a different Q-banding phenotype. Tunisian specimens of R. saharica displayed the plesiomorphic Pelophylax karyotype of 2n = 26 biarmed chromosomes and NORs on the eleventh pair. The Tunisian specimens of D. pictus auritus; had the typical D. pictus 2n = 28 karyotype with the 13th pair of telocentric elements, in contrast to the Spanish auritus specimens that display the chromosomes of this pair shaped as metacentric. Similarities and differences of the four studied Tunisians anuran taxa are discussed with references to published data on their relatives.

The divergence in reproductive features and hybrid fertility patterns between two chromosomal races (2n = 40, 40St, and 2n = 22, 22Rb) of the house mouse in Tunisia were re-assessed on a larger sample of wild and laboratory-bred individuals than studied hitherto. Results showed that litter sizes were significantly smaller in 40St than in 22Rb mice, contrary to previous analyses. This suggests that variation in litter size between the two chromosomal races is more likely related to selective and/or environmental factors acting locally than to interracial reproductive trait divergence. However, the significantly reduced litter size of F 1 hybrids compared with parental individuals was confirmed, and further highlighted a sex difference in hybrid infertility, as F 1 females produced fewer litters and of smaller size than males. Histological analyses of F 1 and backcrosses showed a breakdown of spermatogenesis in males and a significantly reduced primordial follicle pool in females. The degree of gametogenic dysfunction was not related to the level of chromosomal heterozygosity per se, but a significant effect of two Rb fusions on follicle number was observed in hybrid females. These results suggest that genetic incompatibilities contribute to primary gametogenic dysfunction in hybrids between the chromosomal races in Tunisia.

The central coastal region of Tunisia harbours two chromosomal races of the house mouse (2n = 22, 22Rb; 2n = 40, 40Std), which are genetically differentiated and show a high level of reproductive isolation. This study presents an allozyme analysis of house mice from the inland city of Kairouan 75 km from the coastal region. Results showed that the 22Rb and 40Std mice from Kairouan shared the same high degree of variability, and were not genetically differentiated. This contrasts with the genetic data registered for the two chromosomal races from the coastal towns, in which a particularly low genic diversity was observed in the 22Rb populations. As the two races in Kairouan show the same low hybridization rates as the populations in the coastal region, these results argue in favour of a local differentiation of the Rb race in Tunisia, most likely originating in Kairouan. The data further suggest that the decrease in variability observed in the coastal 22Rb populations is related to a founder effect or a bottleneck following the introduction of mice from Kairouan into one of these localities, prior to their dispersion throughout the coastal region.

We examined the population structure and phylogeny of Buthus occitanus (Amoreux, 1789), Androctonus amoreuxi (Audouin & Savigny 1812) and Androctonus australis (Linnaeus, 1758) in Tunisia, using horizontal starch gel and polyacrylamide gel electrophoresis to resolve allozymes at 18 loci. Populations of B. occitanus and A. amoreuxi showed little genetic variation, whereas A. australis populations showed moderate genetic variation. Moreover, despite the restricted dispersal abilities of these species, the allozyme analysis indicated very low levels of intraspecific population differentiation. The Island model of population differentiation best fitted the intraspecific variation, both for mainland populations and for the slightly more differentiated populations from two Mediterranean islands. No diagnostic, fixed alleles were observed between the species of Androctonus, which concurs with the results of nuclear ribosomal DNA analysis. Two subspecies of A. australis, A. a. garzonii Goyffon & Lamy, 1973 and A. a. hector Vachon, 1948, were not resolved by a phylogenetic analysis of the allozyme data. The most likely reasons for the slight population differentiation are either low mutation rates or recent range extensions promoted by human activities. The possibility of indirect gene flow between Androctonus species should also be explored. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81, 255–265.

Aim This study intends to improve our understanding of historical biogeography of olive domestication in the Mediterranean Basin, particularly in the north-western area. Location Investigations were performed simultaneously on olive stones from extant wild populations, extant cultivated varieties from various Mediterranean countries, and archaeological assemblages of Spanish, French and Italian settlements. Methods A combination of morphometrics (traditional and geometrical) allowed us to study both the size and shape of endocarp structure. Concerning shape, a size-standardized method coupled with fitted polynomial regression analysis was performed. Results We found morphological criteria for discriminating between wild and cultivated olive cultivars, and established patterns of morphological variation of olive material according to the geographical origin (for extant material) and to the age of the olive forms (for archaeological material). Levels of morphological convergences and divergences between wild olive populations and cultivated varieties are presented as evidence. Main conclusions Morphological changes of endocarps of olive under domestication at both geographical and chronological scales provide new criteria for the identification of olive cultivars. They allow to determine the origins of cultivated forms created and/or introduced in the north-western Mediterranean regions and to understand how human migrations affected the rest of the Western Mediterranean regions. A model of diffusion of olive cultivation is proposed. It shows evidence of an indigenous origin of the domestication process, which is currently recognized in the north-western area since the Bronze Age.

Two chromosomal races of the house mouse occur in Tunisia, a standard morph (40St) found all over the country, and a derived morph (22Rb) occurring only in central Tunisia. In this region, habitat partitioning between the two morphs was investigated by a microgeographical analysis of their distribution, assessing habitat characteristics and demographic parameters. Results showed that the 22Rb mice always occurred in the oldest sections of towns (medinas), often extending to more recent surrounding neighbourhoods where the 40St morph was most abundant. The latter was never trapped within the medinas. The transition between the two morphs was located within cities in the more recent areas, the hybrid zone being estimated at less than 0.5 km in width by a clinal analysis of chromosomal data. Although differences between habitats exist, almost no demographic differences were found between populations of the two morphs when they occurred in the same or in different habitats. Two hypotheses are discussed to account for the origin of habitat partitioning. The first relies on competitive exclusion of the 40St mice from the medinas by the derived 22Rb mice; the second is based on stochastic processes related to historical evolution of Tunisian urban communities.

This study focuses on the population genetic structure of the green crab Carcinus aestuarii along part of the African Mediterranean coast, with the main target to confirm genetic subdivision across the well documented genetic boundary of the Siculo-Tunisian Strait. For this purpose, the mitochondrial COI (cytochrome oxidase I) gene and five polymorphic microsatellite loci were analysed in 144 and 120 specimens, respectively. Our results show the existence of two distinct haplogroups, separated by 16 mutational steps and revealed a non random distribution of the genetic variation along the African Mediterranean coast. Dating analyses, based on the use of different molecular clock models and rates, placed the divergence among both haplogroups at 1.91 Myr (95% HPD: 1.11–2.68 Myr) to 0.69 Myr (95% HPD: 0.44–0.98 Myr). This range of divergence time estimation corresponds to the Early Pleistocene. The particular pattern of genetic divergence among Eastern and Western African Mediterranean populations of C. aestuarii, detected by 2-level AMOVA at the mitochondrial level, was consistent with that inferred from microsatellite analysis and suggests a vicariant event in C. aestuarii. Demographic reconstruction, inferred from mismatch distribution and BSP analyses, yielded different patterns of demographic history between both African Mediterranean groups. The distribution pattern of the two haplogroups across the African Mediterranean coast, along with results of Bayesian analysis of genetic structure revealing an intermediate geographic group between the two divergent groups of the African coast, support the hypothesis of a secondary contact between two historically isolated groups. Although this hypothetical contact zone, thought to be located near the Siculo-Tunisian Strait, still needs to be verified, the asymmetric gene flow from Western to Eastern African Mediterranean, as inferred by the results of a MIGRATE analysis, reinforces the previously mentioned results.

Specific genetic conditions are known to be associated with high risk of venous thromboembolism. This genetic basis varies widely between ethnic groups. We investigated the distribution of four inherited polymorphisms in 113 unselected Tunisian blood donors by using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method. The allele frequencies of Factor V Leiden (FVL), prothrombin 20210G>A, methylenetetrahydrofolate reductase (MTHFR) 677C>T, and MTHFR 1298A>C mutations were 3, 0.9, 30, and 31%, respectively. The MTHFR 677C>T polymorphism was influenced by age. Twenty‐nine of the 113 blood donors demonstrated more than one genetic markers. Hyperhomocysteinemia was found in 12 subjects, and it was statistically associated to the MTHFR 677TT genotype. Principal component analysis allowed disclosing the resemblance between Mediterranean populations. Our findings may be helpful for population genetics study, and provide epidemiologic database for further studies in thrombosis field among Tunisians. J. Clin. Lab. Anal. 26:167‐173, 2012. © 2012 Wiley Periodicals, Inc.

Phylogeographic structure in marine organisms is ascribed to contemporary and/or historical barriers to dispersal (Benzie and Williams 1997; Waters and Roy 2003). In addition, life history mode can exert a strong influence on the genetic structure of populations (Hart et al. 1997; Riginos and Victor 2001), as illustrated by the consequences of the extreme heterogeneity of dispersal capability on geographic distribution of genetic polymorphism (Kinlan and Gaines 2003). For instance, some species with long-lived planktotrophic larvae show vast geographic distributions and limited genetic structure (Booth and Ovenden 2000; Colgan et al. 2005). Conversely, taxa with brief larval stages or direct development often show marked phylogeographic structure (Collin 2001; Planes et al. 2001; Riginos and Victor 2001). Mitochondrial DNA is commonly used as a genetic marker to infer phylogeographic relationships in most marine organisms (Avise 2000). The gene coding for cytochrome c oxidase subunit I (COI) is among the most frequently used markers because of its high degree of variability (e.g., Avise 2000; Duran et al. 2004a; Lee 2000). Among marine invertebrates, few examples of almost negligible levels of intraspecific variation in COI have been reported for basal phyla such as porifera and anthozoa (Duran et al. 2004b; France and Hoover 2002; Shearer et al. 2002). In asteroids, the COI gene has proven to be highly polymorphic (Flowers and Foltz 2001; Waters et al. 2004).

Genetic diversity of loggerhead turtles, Caretta caretta, nesting on the Kuriat Islands, the most important Tunisian nesting beach (central Mediterranean), was investigated using both nuclear and mitochondrial markers. Allozyme electrophoresis of 63 hatchlings from four different clutches showed a low genetic diversity. The genotypic composition of two clutches did not match Mendelian expectations suggesting the occurrence of multiple paternity. The analysis of 380 bp of the mitochondrial DNA control region revealed no genetic variability. Only one haplotype was described in our sample (N = 16), which corresponds to the sequence of the most common haplotype found on the Mediterranean nesting beaches (CC-A2). The low genetic diversity detected by both mitochondrial and allozyme markers is discussed taking into account available data about past and present situations of loggerhead nesting activity in this site. Adequate conservation measures should be urgently taken to protect the nesting population in this area.

The genetic variation at 21 protein loci was investigated in six natural gilthead seabream (Sparus aurata L., 1758) populations from the Tunisian coast to analyse the amount and distribution of genetic diversity of this species. In the same way, one reared population has been studied. A strong differentiation was detected (D: 0.023-0.083, pairwise FST: - 0.0085-0.2654) between our samples, mainly attributable to the existence of two divergent groups of populations: a southern group located in the Eastern Mediterranean basin and a northern group located in the Western Mediterranean basin. Gene flow between the two groups is probably restricted, which reveals the complexity of the genetic relationships among populations living in the two basins. This divergence was mainly a consequence of the unequal distribution of some alleles and a cline of frequencies in other ones, which were correlated with substantial differences in genetic diversity among regions. The comparison of the genetic diversity detected within populations (H between 0.0556±0.0246 and 0.1857±0.0648) to the range quoted for this species in previous reports revealed that the southern populations presented a similar values to those recorded in Mediterranean and Atlantic populations, whereas the northern populations showed a higher values.

International audience; Three species of scorpions have been reported from Tunisia: Androctonus amoreuxi Audoin, A. aeneas Koch, and A. australis L. The latest has been divided in two subspecies: A. australis garzonii Goyffon & Lamy and A. australis hector Koch. Despite the public health importance of these animals, which cause several cases of poisoning each year, nothing is know about the genetic diversity of the group. To gain a better understanding of the group, we studied the variation of rDNA sequences of the ITS1, 5.8S, and ITS2 region of 14 representatives of the four taxa in Tunisia. The main result is the high polymorphism of the ITS regions. In some instances in both intra- and interspecific comparisons, it was difficult to unambiguously align the sequences. However, some representatives of different species were relatively similar, so that it appeared difficult to recognize the species on the basis of these sequences. A phylogenetic analysis was conducted that inquires the validity of the subspecies status of A. australis garzonii and A. australis hector. Moreover, the taxonomic status of A. aeneas is also questioned. Our studies highlighted the need of a revision of the taxonomy of the scorpions in Tunisia; however, the use of other genetic markers will be necessary to solve this question.

In wild populations of the house mouse from Tunisia, fluctuating asymmetry and character size of tooth traits were compared between chromosomal races (2n = 40, all acrocentric standard karyotype, and 2ni = 22, with nine fixed Robertsonian fusions) and their natural hybrids. Developmental stability was impaired in hybrids compared to both parental groups. Because genetic divergence measured by allozyme markers was low, genomic incompatibilities were not expected between the chromosomal races. This suggests that differentiation of gene systems specifically involved in development may have occurred between the chromosomal races. Support for the latter was found in the study of character size which showed that the 2n = 22 mice had smaller teeth than either the hybrid or the standard mice. The study of Tunisian chromosomal races thus shows that chromosomal evolution may lead to important changes in coadapted gene systems without involving extensive genic differentiation.