Search publications of the members of the Royal Belgian institute of natural Sciences
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Presence of Anopheles culicifacies B in Cambodia established by the PCR-RFLP assay developed for the identification of Anopheles minimus species A and C and four related species
- A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay developed for identification of five species of the Anopheles minimus Theobald group and a related mosquito species of the Myzomyia Series (Diptera: Culicidae) was applied to morphologically identified adult female specimens collected in Ratanakiri Province, north-eastern Cambodia. In addition to finding An. aconitus Dönitz, An. minimus species A and An. pampanai Büttiker & Beales, some specimens showed a new restriction banding pattern. Siblings of specimens that exhibited this new PCR-RFLP pattern were morphologically identified as An. culicifacies James sensu lato. Based on nucleotide sequences of the ribonuclear DNA internal transcribed spacer 2 region (ITS2) and the mitochondrial cytochrome oxidase I gene (COI), these specimens were recognized as An. culicifacies species B (sensu Green & Miles, 1980), the first confirmed record of the An. culicifacies complex from Cambodia. This study shows that the PCR-RFLP assay can detect species not included in the initial set-up and is capable of identifying at least seven species of the Myzomyia Series, allowing better definition of those malaria vector and non-vector anophelines in South-east Asia.
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The east carpathian loess record: A reference for the middle and late Pleniglacial stratigraphy in central Europe [La sequence loessique du domaine est-carpatique: Une référence pour le pléniglaciaire moyen et supérieur d'Europe centrale]
- The East Carpathian regional sequence established for the middle and late pleniglacial loess is based on records from the Palaeolithic sites Molodova V (Ukraine), Mitoc-Malu Galben (Romania) and Cosautsi (Moldova). The special importance of this long sequence lies 1) in the high quality of the pedosedimentary and climatic records favoured by the position of the three sites within the terrace system of the Dniester and Prut basins and 2) in the high chronological resolution within the period posterior to 33,000 BP determined by the archaeological context of the multilayered Palaeolithic sites. A large number of these layers with a quite regular distribution within the sequence appeared to be rich in good quality organic material for accurate radiometric dating. This made possible to establish a well documented pedosedimentary and climatic succession encompassing the main part of the middle pleniglacial and almost the whole upper pleniglacial, with a resolution degree around one millennium or several centuries. The analysis of this new sequence revealed a quite coherent internal structure that illustrates the complexity of the sedimentary and climatic dynamics within the time span 33,000-10,000 BP.
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Palynology, paleoenvironments, and organic carbon isotope evolution in lagoonal Paleocene-Eocene boundary settings in North Belgium
- Integration of new data in sedimentology, micropaleontology and carbon isotope analysis of the Paleocene-Eocene boundary sequence in northern Belgium enables differentiation of a series of biotic and tectonic events, generally associated with the brief episode of global warming, known as the Initial Eocene Thermal Maximum (IETM, formerly LPTM), and to establish their succession in time. The onset of the carbon isotope excursion (CIE), positioned at the base of the Tienen Formation, is shown to precisely coincide with the onset of a massive Apectodinium abundance, and to be coincident or very close to the development of deeply incised paleovalleys. The organic carbon isotope curve recorded in the lagoonal settings of northern Belgium, presents a complex structure, marked by multiple anomalies and, consequently, is not believed to result from a single instantaneous event. The most negative values (-26\%) are recorded in the Apectodinium-dominated interval (75\%) in the lower part of the Tienen Formation. However, the range of the Apectodinium acme (50\%) suggests that the IETM probably lasted until the end of the deposition of the Tienen Formation. The kaolinite influxes at its base and within its middle part are proved to be unrelated to the CIE. The integration of the dinoflagellate cyst and the carbon isotope data has led to the establishment of a refined chronostratigraphic framework, allowing the depositional history of the southern North Sea Basin to be deciphered. During pre-IETM and post-IETM times widely uniform marine depositional regimes existed throughout the area because of tectonic quiescence. This strongly contrasted with the IETM interval, which is marked by restricted complex lagoonal conditions and differential subsidence. In spite of the extreme warm climate and the tectonic instability of the area, vegetation was relatively stable across the IETM and marked by low extinction and first-occurrence rates. © 2003 Geological Society of America.
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A perspective on the importance of reproductive mode in astrobiology
- Reproduction is a vital characteristic of life, and sex is the most common reproductive mode in the eukaryotic world. Sex and reproduction are not necessarily linked mechanisms: Sexuality without reproduction exists, while several forms of asexual reproduction are known. The occurrence of sexuality itself is paradoxical, as it is very costly in evolutionary terms. Most of the hypotheses (more than 20) attempting to explain the prevalence of sex fall into two categories: Sex either creates good gene combinations for adaptation to environments or eliminates bad gene combinations counteracting the accumulation of mutations. In spite of this apparent wealth of beneficial effects of sex, asexuality is not rare. Most eukaryotic, asexual lineages are short-lived and can only persist through the presence of sexual roots, but at least two animal groups, bdelloid rotifers and darwinulid ostracods, seem to claim the status of ancient asexuals. Research on (a)sexuality is relevant to astrobiology in a number of ways. First, strong relationships between the origin and persistence of life in extreme environments and reproductive mode are known. Second, the "habitability" of nonterrestrial environments to life greatly depends on reproductive mode. Whereas asexuals can do equally well or better in harsh environments, they fail to adapt fast enough to changing abiotic and biotic environments. Third, it has been shown that plants reproduce mainly asexually in space, and sperm production and motility in some vertebrates are hampered. Both findings indicate that extraterrestrial life under conditions different from Earth might be dominated by asexual reproduction. Finally, for exchange of biological material between planets, the choice of reproductive mode will be important. © Mary Ann Liebert, Inc.
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Valve surface structure of Candona neglecta Sars, 1887 (Crustacea, Ostracoda)
- The valves of Candona neglecta Sars, 1887, a common freshwater ostracod occurring throughout the Holarctic, were formerly described to bear tiny tubercles and spinules. It is here shown with the help of the scanning electron microscope that the valves of this species actually appear to be smooth. The tubercles and spinules described by previous authors correspond to conspicuously wide pore canals that mimic tiny surface structures when observed in the stereomicroscope. The taxonomic importance of this character is briefly discussed and a diagnosis of the neglecta-group of Candona Baird, 1845 is given. The genus name Neglecandona, which was introduced in 2001, is unavailable in the sense of the International Code of Zoological Nomenclature.
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Meris imagery of belgian coastal waters: Mapping of suspended participate matter and chlorophyll-A
- This paper describes a first application-oriented analysis of MERIS products for Suspended Particulate Matter (SPM) and Chlorophyll-a (CHL) concentration in Belgian coastal waters. Regional algorithms designed for Belgian waters have been implemented and compared with the standard MERIS products, termed Total Suspended Matter and Algal2 respectively. The standard and regional SPM products seem robust and give similar data. Notwithstanding a more complete match-up validation analysis, these products seem sufficiently mature for use in applications such as sediment transport model validation. Results for CHL products are less convincing and further analysis is required before this data can be reliably used. In particular the MERIS Product Confidence flags have not yet been validated. The red and near infrared bands are particularly important in turbid coastal waters and should be considered a priority for further validation. MERIS full resolution mode is attractive for SPM mapping when compared with other sensors. For CHL mapping in coastal waters the superior spectral resolution and algorithm design give MERIS a distinct advantage over other ocean colour sensors. The disadvantages of MERIS, particularly for SPM mapping, are the reduced frequency (related to swath and sunglint) and availability of data.
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Mapping of chlorophyll and suspended particulate matter maps from CHRIS imagery of the oostende core site
- The image set created on 5 August 2003 by CHRIS/PROBA is analyzed to assess the feasibility of producing suspended particulate matter (SPM) and chlorophyll (CHL) maps. To produce these maps images are first destriped, atmospherically corrected and georeferenced. Once the data processing is finished, the results are compared with seaborne measurements and data products retrieved from other ocean colour sensors. The data processing with its associated problems, the comparison with seaborne and other data and the creation of SPM and CHL maps are described in this paper. Conclusions and recommendations are made in the context of considering CHRIS/PROBA as a model for the future generation of small ocean colour missions.
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Abundance and production of riparian trees in the lowland floodplain of the Queets River, Washington
- Riparian zones associated with alluvial rivers are spatially dynamic, forming distinct vegetative mosaics that exhibit sharp contrasts in structure and processes related to the underlying biophysical template. The productivity of riparian plants, especially trees, influences streamside community characteristics as well as the forms and fluxes of organic matter to adjacent streams - thereby strongly impacting patterns of channel morphology, water flow, sedimentation, and habitat in rivers. As part of a comprehensive investigation of riparian dynamics in coastal rain forest rivers of the Pacific Northwest (USA), we examined riparian tree abundance (density, basal area, and biomass) and rates of production (basal area growth [BAI] and bole wood biomass increase [P]) of seven common species - red alder (Alnus rubra), Sitka spruce (Picea sitchensis), bigleaf maple (Acer macrophyllum), western hemlock (Tsuga heterophylla), black cottonwood (Populus trichocarpa), vine maple (Acer circinatum) and willow (Salix spp.) - in the lowland floodplain of the Queets River (Olympic National Park), Washington. Measurements were made annually for three years (1999 - 2001) in 16 permanent plots on three biophysical templates that formed a toposequence - active floodplain, young terrace and mature terrace. Stem density was highest in the active floodplain (∼27,000 stems/ ha), decreasing in the young terrace (∼2,700 stems /ha) and the mature terrace (∼500 stems/ha). Basal area and total stem biomass were lowest in the active floodplain (∼16 m2/ha and ∼18 Mg dry weight/ha, respectively) and higher on the young terrace (∼32 m2/ha and ∼134 Mg dry weight/ha) and on the mature terrace (∼69 m2/ha and ∼540 Mg dry weight /ha). Total plot-scale BAI was not significantly different among the physical templates with mean values ranging from approximately 1.4 (low terrace) to approximately 2.8 m2/ha/y (active floodplain). In contrast, P was significantly higher on the mature terrace (10.3 Mg/ha) than the active floodplain (3.2 Mg/ha) but there was no significant difference between young terrace (6.5 Mg/ha) and mature terrace. For the entire Queets River floodplain (57 km2 over 77 km of river length), the mature terrace contributed 81\% of the total annual production (28,764 Mg) whereas the active floodplain and young terrace accounted only for 5 and 14\%, respectively. Overall, we show that riparian trees grow quickly in this coastal Pacific Northwest system and that the older riparian forests on mature terraces are the main contributors to stem production at the plot and floodplain scales for at least 350 years after stand initiation. This suggests that, in combination with the rapid lateral migrations of many alluvial rivers, the older riparian forests on those terraces are important and sustained sources of organic matter (especially large woody debris, LWD) that, over decades to centuries, shape the character of coastal rivers in the Pacific Northwest. © 2005 Springer Science+Business Media, Inc.
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Effects of environmental pollution on microsatellite DNA diversity in wood mouse (Apodemus sylvaticus) populations
- Ten microsatellite DNA loci were surveyed to investigate the effects of heavy metal pollution on the genetic diversity and population genetic structure of seven wood mouse (Apodemus sylvaticus) populations along a heavy metal pollution gradient away from a nonferrous smelter in the south of Antwerp (Flanders, Belgium). Analysis of soil heavy metal concentrations showed that soil Ag, As. Cd, Cu, and Pb decreased with increasing distance from the smelter. Genetic analyses revealed high levels of genetic variation in all populations, but populations from the most polluted sites in the gradient did not differ from those of less-polluted sites in terms of mean observed and expected heterozygosity level and mean allelic richness. No correlation was found between measures of genetic diversity and the degree of heavy metal pollution. However, an analysis of molecular variance and a neighbor-joining tree suggested a contamination-related pattern of genetic structuring between the most polluted and less polluted sites. Pairwise FST values indicated that populations were significantly genetically differentiated, and assignment tests and direct estimates of recent migration rates suggested restricted gene flow among populations. Additionally, genetic differentiation increased significantly with geographical distance, which is consistent with an isolation-by-distance model. We conclude that, at least for our microsatellite DNA markers, genetic diversity in the studied wood mouse populations is not affected greatly by the heavy metal pollution. © 2005 SETAC.
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Seasonal variation of floc characteristics on tidal flats, the Scheldt estuary
- The flocculation mechanism dominates the fate of suspended matter in the estuarine environment. By modifying the texture of suspended matter, flocculation is one of the principle factors determining the transport and deposition of suspended matter in estuaries. Surveys of the seasonal variation of dispersed particle and non-dispersed particle characteristics, organic matter content as well as suspended matter deposition in two contrasting intertidal environments, one freshwater and one brackish water, in the Scheldt estuary were undertaken at fortnightly intervals for a year. The study of non-dispersed particle, i.e. floc, is mainly focused on floc size, shape, and microstructure, properties presumed to be significant in the suspended matter transport processes in the estuary. In this study, floc size as well as floc sphericity correlate positively with the change of organic matter content and reveal that floc grows in a three-dimensional way with increasing organic matter. It is observed that relatively condensed, small and elongated flocs appear in winter and spring periods, while loose, large and spherical flocs occur during the summer. The study also reveals that suspended matter transported as dense flocs with size range of ca. 105-250 μm have a greater effect on its short-term deposition than loose flocs with size range of ca. 250-500 μm. As the measured suspended matter deposition is much higher in winter-spring than in summer, it is deduced here that highly compact and relatively dense flocs contribute to deposition during winter and spring periods resulting in a stable layer, while loosely formed flocs likely lead to an easier erodible layer during the summer. This study concludes that floc structure-related density is a more significant parameter than floc size in the suspended matter deposition processes. © Springer 2005.
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Suspended matter in the Scheldt estuary
- The Scheldt estuary is characterised by a specific energy pattern resulting from the interaction of wave energy, tidal energy and river energy. It divides the estuary into three parts and governs suspended matter transport and distribution pattern. Observation of suspended matter transport shows the existence of three estuarine turbidity maxima (ETM), a marine-dominated ETM in the lower estuary at the river mouth, a river-dominated ETM in the upper estuary with suspended matter concentration reaching up to 300 mg/l, and the most important tide-dominated ETM in the middle estuary with suspended matter concentrations from several hundred milligrams per litre up to a few grams per litre. Resuspension is the dominant phenomenon in this last ETM due to the tidal related bottom scour, which is initiated when a critical erosion velocity of 0.56 m/s is exceeded. An assessment of residual current along the axis of the estuary shows distinctive pattern between the surface water flow and the near bottom water flow. Also the local morphology of the river, natural or man-made, has a prominent effect on the orientation and strength of the residual currents flowing along either side of the river or river bend. Evaluation of suspended matter concentration in relation to the current flow shows no systematic correlation either because of phenomena as scour lag and settling lag mainly in the middle estuary, or because of the current independency character of uniform-suspension mainly in the upper and lower estuary. Quantification of suspended matter load exhibits a net downstream transport from the upper estuary, a near-equilibrium sustainable status in the middle estuary and a net upstream transport of suspended matter from the lower estuary. The characteristic of suspended matter is induced by and is a function of e.g. tidal phase, spring-neap tide, longitudinal and vertical distribution mechanisms, seasons, short and long terms of anthropogenic influence and/or estuarine maintenance. Suspended matter is dominated by complex and cohesive organo-mineral aggregates. It consists of a variable amount of an inorganic fraction (average of 89\%) and an organic fraction and occurs largely as flocs, the size of which is remarkably larger in the upper estuary and smallest within the ETM in the middle estuary. Independent time series measurements (1990-2000) of suspended matter property show an increasing sand fraction, a decreasing organic matter content, a rise in δ13C as well as a decrease in water transparency. These independent measurements exhibit coherent consequences of estuarine maintenance operations. Maintenance dredging of the shipping channel and harbours and dumping operation in the Scheldt strengthen marine influence further landward, resulting in a sustained tidal range increment and upstream flow and transport of suspended matter. © Springer 2005.
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Restoration of tropical peat swamp rotifer communities after perturbation: An experimental study of recovery of rotifers from the resting egg bank
- In order to assess the recovery potential of tropical freshwater communities after disturbance, we performed an experimental study on the effects of exposure conditions and durations of storage on hatching of rotifer resting eggs in sediment. Well-mixed surface sediment samples from Mai Khao peat swamp on Phuket Island, Thailand, were stored under three conditions (cold -4°C & dark: CD; ambient -32-42°C & dark: AD; and ambient & daylight conditions: AL), for different periods of time (1, 2, 4, 6, 12, 18 and 24 months). The number of species hatching from the sediment was significantly affected by treatment for both short- (1-6 months) and long-term (6-20 months) exposure. Significant effects of short- and long-term exposure within treatments were also present. Both factors interacted significantly. Regarding numbers of specimens hatching, no short-term effects of differences in treatment condition were found, but increasing the duration did have an effect. Significant effects of treatment occurred after 6 months, in addition to prolonged effects of duration. Again, both factors interacted significantly. These experiments indicate that exposure time has a strong impact on the viability of resting eggs, whereas, an effect of exposure condition appears only after 6 months. So, recovery of rotifer communities from resident sediment egg banks in disturbed peat swamps can only be effectively attained when restoration occurs within a relatively short period after perturbation. © Springer 2005.
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Phylogenetic systematics of the Empis (Coptophlebia) hyalea-group (Insecta: Diptera: Empididae)
- Six clades are inferred from a phylogenetic analysis including 42 species belonging to the Empis (Coptophlebia) hyalea-group. These clades are named as follows: E. (C.) acris, E. (C.) aspina, E. (C.) atratata, E. (C.) hyalea, E. (C.) jacobsoni and E. (C.) nahaeoensis. The presence of two dorsal more or less developed epandrial projections is considered autapomorphic for the E. (C.) hyalea-group in addition to two characters previously found to support the monophyly of this group (presence of an unsclerotized zone in the middle of labella and epandrium unpaired). Amongst the cladistically analysed species, 24 are newly described [E. (C.) acris, E. (C.) aspina, E. (C.) cameronensis, E. (C.) duplex, E. (C.) incurva, E. (C.) inferiseta, E. (C.) kuaensis, E. (C.) lachaisei, E. (C.) lamellalta, E. (C.) lata, E. (C.) loici, E. (C.) longiseta, E. (C.) mengyangensis, E. (C.) menglunensis, E. (C.) missai, E. (C.) nimbaensis, E. (C.) padangensis, E. (C.) parvula, E. (C.) projecta, E. (C.) pseudonahaeoensis, E. (C.) submetallica, E. (C.) urumae, E. (C.) vitisalutatoris and E. (C.) woitapensis], five are reviewed [E. (C.) hyalea Melander, E. (C.) jacobsoni De Meijere, E. (C.) ostentator Melander, E. (C.) sinensis Melander and E. (C.) thiasotes Melander] and 13 were recently described in two previous papers. Two additional species, E. (C.) abbrevinervis De Meijere and E. (C.) multipennata Melander, are also reviewed but not included in the cladistic analysis since they are only known from the female. A lectotype is designated for E. (C.) jacobsoni. A key is provided to the six clades of the E. (C.) hyalea-group as well as to species of each clade. A catalogue of the E. (C.) hyalea-group, including 72 species, is given. The taxonomic status of 25 additional species mainly described by Bezzi and Brunetti, from the Oriental and Australasian regions, is discussed. The E. (C.) hyalea-group is firstly recorded from the Palaearctic Region and Australia. Finally, the distribution and the habitats of the species compared with their phylogeny suggest a possible relationship between the diversification of the group and forest fragmentations during the Quaternary. © 2005 The Linnean Society of London.
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Empidine dance flies from Singapore and southern Malaysia (diptera: Empididae: Empidinae)
- Five new species belonging to the Empis (Coptophlebia) hyalea-group are described, namely E. (C.) neesoonensis, new species, E. (C.) producta, new species, E. (C.) tortuosa, new species, E. (C.) triseta, new species and E. (C.) verruca, new species. A key to all known species of the group is provided for Singapore and Southern Malaysia. © National University of Singapore.
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Atypical mating behaviour in the empidine dance fly Rhamphomyia (Lundstroemiella) magellensis (Diptera : Empididae : Empidinae)
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Spatiotemporal allozyme variation in the damselfly, Lestes viridis (Odonata: Zygoptera): Gene flow among permanent and temporary ponds
- Several insect species seem to persist not only in permanent but also in temporary ponds where they face particularly harsh conditions and frequent extinctions. Under such conditions, gene flow may prevent local adaptation to temporary ponds and may promote phenotypic plasticity, or maintain apparent population persistence. The few empirical studies on insects suggest the latter mechanism, but no studies so far quantified gene flow including both pond types. We investigated the effects of pond type and temporal variation on population genetic differentiation and gene flow in the damselfly Lestes viridis in northern Belgium. We report a survey of two allozyme loci (Gpi, Pgm) with polyacrylamide gel electrophoresis in 14 populations from permanent and temporary ponds, and compared these results with similar data from the same permanent populations one year before. The data suggested that neither pond-drying regime, nor temporal variation have a substantial effect on population genetic structuring and did not provide evidence for stable population differentiation in L. viridis in northern Belgium. Gene flow estimates were high within permanent and temporary ponds, and between pond types. Our data are consistent with a source-sink metapopulation system where temporary ponds act as sinks in dry years, and are quickly recolonized after local population extinction. This may create a pattern of apparent population persistence of this species in permanent and temporary ponds without clear local adaptation. © Springer 2005.
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Mitochondrial DNA variation and cryptic speciation within the free-living marine nematode Pellioditis marina
- An inverse correlation between dispersal ability and genetic differentiation among populations of a species is frequently observed in the marine environment. We investigated the population genetic structure of the free-living marine nematode Pellioditis marina. A total of 426 bp of the mitochondrial cytochrome oxidase subunit 1 (COI) gene were surveyed on a geographical scale of approximately 100 km during spring 2003. Nematodes were collected from 2 coastal locations in Belgium, and from 2 estuaries and a saltwater lake (Lake Grevelingen) in The Netherlands. Molecular variation was assessed with the single-strand conformation polymorphism (SSCP) method. In total, 32 different haplotypes were observed, and sequence divergence among 452 individuals ranged from 0.2 to 10.6\%. We discovered 4 distinct mitochondrial lineages, with low divergences within the lineages (0.2 to 1.6\%) and high divergences between the lineages (5.1 to 10.6\%). The nuclear ribosomal ITS (internal transcribed spacer) region showed concordant phylogenetic patterns, suggesting that nematode species diversity may be considerably underestimated. Analysis of molecular variance (AMOVA) indicated a strong genetic differentiation among populations. The Lake Grevelingen population was clearly differentiated from all other populations, but genetic structuring was also significant within the Westerschelde and was correlated with gradients in salinity and pollution. The observed population genetic structure is in accordance with the limited active dispersal capacity of P. marina, but is at variance with its significant potential for passive dispersal. We therefore suggest that autecological characteristics, including short generation time, high colonization potential and local adaptation, may be at the basis of this nematode's population genetic structure. © Inter-Research 2005.
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A wingless intertidal ground beetle, new to the Belgian fauna, in the river IJzer estuary nature restoration site: Bembidion nigropiceum Marsham, 1802
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Bottlenecks, drift and differentiation: The fragmented population structure of the saltmarsh beetle Pogonus chalceus
- We investigated the distribution of genetic variation within and between 10 fragmented populations of the saltmarsh beetle Pogonus chalceus in the region of Flanders (Belgium) representing all extant populations of the species in that region by using allozyme and microsatellite markers. Beetle population size and habitat area failed to explain a significant part of the genetic variability. Microsatellite allelic diversity was sensitive to population size differences but not to saltmarsh area estimates. Heterozygosities of both marker types and allozyme allelic diversity on the other hand showed no significant correlation to population size and saltmarsh area. There was also no correlation between geographical and genetic distances among populations. Evidence was found for past bottlenecks in some of the smallest populations. Maximum likelihood methods using the coalescent approach revealed that the proportion of common ancestors was also high in those small populations. 35\% of our studied individuals, especially in the largest populations showed a relative wing size smaller than 70\%. Moreover, only six out of the 10 studied populations showed a few individuals with functional flight musculature. In conclusion, the overall pattern of distribution of genetic variation and the low flight capacity did not support an equilibrium model of population structure in P. chalceus, but mainly suggested a lack of regional equilibrium with both drift and gene flow influences. © Springer 2005.
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Genetic differentiation among populations of the salt marsh beetle Pogonus littoralis (Coleoptera: Carabidae): A Comparison between Atlantic and Mediterranean populations
- Genetic differentiation was studied among populations of the salt marsh beetle Pogonus littoralis (Coleoptera: Carabidae), comparing Atlantic and Mediterranean populations over a large part of its range. The genetic structure of this highly mobile beetle was investigated by studying allozyme polymorphism at nine enzyme loci in 13 populations. Mediterranean P. littoralis were highly significantly differentiated from Atlantic populations. Moreover, more isolated Atlantic populations showed increased differentiation and decreased genetic diversity compared to less fragmented Mediterranean populations. © The American Genetic Association. 2005. All rights reserved.
