Cretan HLA genetics supports its early Minoan culture as a link between North Africa and Europe

HLA studies in Crete show that this population is related to North Africans and also Iberians. This may be a reflection of a common prehistoric first Europeans relationships with North Africans and drying Saharan emigration after 10,000 years BC; it may be specifically represented by a primitive and early cult to the bull in both Cretan (Minoan) and Iberian populations. In the present study, unrelated Cretans representing different Island parts have been studied for class II HLA-DRB1 and -DQB1 alleles. The most frequent ones were HLA-DRB1*11:01 and HLA-DRB1*07:01 and HLA-DQB1*03:01 and DQB1*05:01. Also, the Cretan HLA class II haplotype HLA-DBR1*11:01-DQB1*03:01 had the highest frequency and is also common to other Mediterraneans, including Iberians. In addition, DRB1*07:01-DQB1*02:01 and HLA-DRB1*04:02-DQB1*03:02 Cretan haplotypes are shared with North Africans (the latter with Algerians, Tunisians and Moroccans). In summary, Crete was one of the first European classic cultures (Minoan) which was probably an early link, like Iberia, between North Africa /Sahara and Europe,also supported by genetic results.

Crimean-Congo Hemorrhagic Fever Virus Seropositivity among Dromedary Camels, Algeria, 2020-2021

Serosurvey results for Crimean-Congo hemorrhagic fever virus antibodies in dromedary camels in Algeria indicate that the pathogen is circulating endemically in desertic areas, despite the hostile environment. Thus, dromedaries are suitable sentinels for detecting human risk for Crimean-Congo hemorrhagic fever in desertic areas.

Saharan, Aral-Caspian and Middle East dust travels to Finland (1980-2022)

Studies on atmospheric dust and long-range transport of mineral dust have been a focus of atmospheric science in recent years. With its wide range of direct and indirect effects, mineral dust is one of the most uncertain elements in the mechanisms of climate change, and a deeper understanding of its role is essential for understanding future processes. The aim of our research was to provide the first systematic data on the so far episodically documented northward transport mineral dust from arid-semiarid areas. So, in this paper, we present dust storm events from lower latitudes reaching the Finnish atmosphere, based on the MERRA-2 model Dust Column Mass Density data and after a multistep verification procedure using independent data source. In total, 86 long-range dust storm events were identified between 1980 and 2022, when air masses loaded with dust reached Finland. Based on backward-trajectories different sources were identified: 59 were Saharan, 22 were Aral-Caspian, and five were associated with Middle Eastern source areas. Considerable variation in inter-annual frequencies was observed among the source areas, which may be due to changes in circulation conditions and the effects of human activity (agriculture and land use changes in Aral Sea region). There is a clear maximum of dust events in spring (60%), followed by summer and autumn (where 10 of the 11 autumn episodes were from the Sahara). However, the number and proportion of scarce winter events have more than doubled since 2010 compared to the preceding 30 years, but no autumn events were registered during this period. This clear temporal variation coincides with changes in dust transport observed in other regions of Europe, driven by greater atmospheric meridionality associated with climate change and driven by reduced temperature difference between low and high latitudes due to enhanced temperature increases at Arctic regions.

Feeding Ecology of the Cuvier's Gazelle (Gazella cuvieri, Ogilby, 1841) in the Sahara Desert

Knowledge of the feeding ecology of ungulates in arid biomes offers an interesting model for understanding the drought resistance of large desert-adapted herbivores, a crucial issue in the face of increasing desertification due to climate change. To assess the feeding ecology of the endangered Cuvier's gazelle (Gazella cuvieri) in the Sahara desert, we used a multi-method approach combining faecal samples, direct observations, and the recording of indirect signs of feeding. We hypothesised that browser behaviour is the best foraging strategy for species living in hyper-arid environments, mainly due to long periods without grazing opportunities. Complementarily, we explored the effects of the main environmental descriptors (rainfalls and NDVI) on feeding patterns and diet quality. We found that Cuvier's diets are based mainly on acacias (Vachellia tortilis, V. flava) and occasionally on the annual forb Anastatica hierochuntica. In total, eighteen species (five trees, nine shrubs, three herbs, and one grass) belonging to fifteen families were recorded. Our result confirmed the browsers' characteristic of this species, reaffirming its ability to settle in a hostile environment. Acacias stand out as key species consumed at the southernmost limit of their range; hence, future conservation plans and strategies should take this into account for the survival of Cuvier's gazelle in desert environments.

Long-term projection of future climate change over the twenty-first century in the Sahara region in Africa under four Shared Socio-Economic Pathways scenarios

Climate change affects air quality and people's health. Therefore, accurate prediction of future climate change is of great significance for human beings to better adapt and mitigate climate change. Using the projection simulation dataset of the CMIP6 multi-model ensemble, the future climate change in the Sahara region under the four scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) is analyzed. The results show that annual and seasonal average surface air temperature in the Sahara region will continue to rise throughout the twenty-first century relative to the baseline period 1995-2014 if greenhouse gas (GHG) concentrations continue increasing. Under the four SSPs scenarios, the warming in the Sahara region will be more pronounced than in the whole world through the twenty-first century. The annual maximum temperature (TX), the annual minimum temperature (TN), the annual count of days with maximum temperature above 35 °C (TX 35), and the annual count of days with maximum temperature above 40 °C (TX 40) in the Sahara region will continue to increase until the end of the twenty-first century under the four scenarios. The results of climate change prediction can provide scientific reference for climate policy-making.

Culturing the desert microbiota

Over the last 30 years, the description of microbial diversity has been mainly based on culture-independent approaches (metabarcoding and metagenomics) allowing an in-depth analysis of microbial diversity that no other approach allows. Bearing in mind that culture-dependent approaches cannot replace culture-independent approaches, we have improved an original method for isolating strains consisting of "culturing" grains of sand directly on Petri dishes (grain-by-grain method). This method allowed to cultivate up to 10% of the bacteria counted on the surface of grains of the three sites studied in the Great Western Erg in Algeria (Timoudi, Béni Abbès, and Taghit), knowing that on average about 10 bacterial cells colonize each grain. The diversity of culturable bacteria (collection of 290 strains) predicted by 16S rRNA gene sequencing revealed that Arthrobacter subterraneus, Arthrobacter tecti, Pseudarthrobacter phenanthrenivorans, Pseudarthrobacter psychrotolerans, and Massilia agri are the dominant species. The comparison of the culture-dependent and -independent (16S rRNA gene metabarcoding) approaches at the Timoudi site revealed 18 bacterial genera common to both approaches with a relative overestimation of the genera Arthrobacter/Pseudarthrobacter and Kocuria, and a relative underestimation of the genera Blastococcus and Domibacillus by the bacterial culturing approach. The bacterial isolates will allow further study on the mechanisms of tolerance to desiccation, especially in Pseudomonadota (Proteobacteria).

Parasites of Moroccan desert Coptodon guineensis (Pisces, Cichlidae): transition and resilience in a simplified hypersaline ecosystem

Sebkha Imlili (Atlantic Sahara) is a salt flat with over 160 permanent holes of hypersaline water generated in the Holocene and inhabited by euryhaline organisms that are considered to be relics of the past, including the cichlid fish Coptodon guineensis. We surveyed the fish parasites four times over one year, to i) identify the parasites, and ii) determine possible seasonality in infection patterns. Over 60% of the fish were infected by one to three helminths: an acanthocephalan in the intestine and two digenean metacercariae in the kidney, spleen, liver, muscle, and mesenteries. The acanthocephalan Acanthogyrus (Acanthosentis) cf. tilapiae was identified morphologically and molecularly; only one digenean (the heterophyid Pygidiopsis genata) could be identified molecularly. Both identified parasites were present throughout the sampling periods; the unidentified metacercariae were present only in summer and fall. Mean intensities, but not prevalence of infection by the acanthocephalan, reflected a biannual pattern of transmission. Infection accrued with fish size, possibly due to cannibalism. Because the water holes include only a few invertebrates, the intermediate hosts of these parasites can be inferred to be the gastropod Ecrobia ventrosa for the digeneans and either the copepod Cletocamtpus retrogressus or the ostracod Cyprideis torosa for the acanthocephalan. This ecosystem appears stable and provides a window into the past, as the acanthocephalan likely switched from freshwater tilapia to C. guineensis when the Sebkha formed. However, this is a vulnerable environment where the survival of these parasites depends on interactions maintained among only very few hosts.

Assessment of heavy metals and macromineral in frequently used medicinal plants from Algerian Sahara traditional ethnopharmacopeia

In this study, a total of 15 elements, both physiological and causing toxic effects, have been determined in 9 medicinal plants collected from their natural environment in the Algerian Sahara regions. The concentrations of elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion and by the X-ray fluorescence spectrometry (XRF). By analyzing the spiked test and the reference materials, the accuracy of the measurements was determined. Our findings show differences in elements composition and concentration between the species under investigation, indicating differences in physiological function of the plant as a result of elemental interactions within it. The elements were quantified (in μg/g): Br (0.04-5.44), Cd (1.21-1.34), Co (1.12-64.35), Cr (1.51-59.05), Cu (1.81-9.28), Fe (94.26-668.55), Mn (16.34-70.77), Ni (1.5-53.64), Pb (1.18-2.55), Zn (1.21-310.80) and (in mg/g): Ca (4.23-4.70), Cl (21.98-117.91), P (28.92-30.49), S (4.15-11.95), Si (1.99-2.36). Mean element levels in medicinal plants were established in decreasing order as follows: Zn>Mn>Cu>Cr>Ni>Pb>Cd>Co. Except for nickel, which reached 53.64μg/g in the Capparis spinosa L species, heavy metal concentrations were found to be low in all samples. Based on traditional use, we can cautiously conclude that these medicinal plants pose no risk to users.

Adaptation of Some Quinoa Genotypes (Chenopodium quinoa Willd.), Grown in a Saharan Climate in Algeria

Agriculture in southern Algeria faces several challenges that hinder its development, including drought, high temperatures and the excessive salinity of soil and groundwater. The introduction of crops resistant to these factors is one of the solutions chosen to address these abiotic constraints. This research aimed to evaluate the behavior of quinoa (Chenopodium Quinoa Willd.) grown in the Ouargla region of southeastern Algeria. Five varieties of quinoa (Santa maria, Giza1, Amarilla Sacaca, Blanca de Junin and Kancolla) were tested at two sites that differed in terms of soil salinity (9.95 mS/cm and 0.85 mS/cm) during 2019 and 2020. A complete random block experimental design with four repetitions was used for the agronomic tests. Our results clearly show that higher grain yields were obtained at the high salinity site (site 1) compared to the low salinity site (site 2). However, plant height, grain yield per plant and harvest index differed between varieties and sites. In contrast, stem diameter was not greatly affected by salinity. The varieties that seem to be best adapted to the growing conditions of the Ouargla region are, in descending order: Santa Maria, Giza1, Amarilla Sacaca and Blanca de Junin. When testing quinoa in new environments, it is critical to adapt the cropping cycle of varieties to avoid very high temperatures. The choice to switch to winter cultivation instead of spring cultivation can be an essential criterion for success. The biogeographical approach conducted in this research opens up new perspectives for the adaptation and cultivation of quinoa outside its region of origin to satisfy the food security of the people of North Africa.

Saharan air outflow variability in the 1980-2020 period

Airborne dust represents a hazard to the environment and human health. The outflow of air masses carrying dust from northern Africa, the world's largest active dust source, to the North Atlantic and Mediterranean regions is modulated by atmospheric conditions. However, how global warming-driven changes on atmospheric circulation have influenced North African air outflow in the recent past is not well understood. Here, we explore the Saharan air outflow from northwestern Africa over the 1980 to 2020 period. We find a decrease in the transport to the Atlantic Ocean and the Iberian Peninsula of -0.29 ± 0.16% dec^-1 and -0.66 ± 0.18% dec^-1, respectively, and an increasing trend to the Mediterranean Sea (0.24 ± 0.18% dec^-1) and Europe (0.60 ± 0.18% dec^-1). The results indicate that the strengthening of the Atlantic high pressure system and the Saharan thermal low, both associated with the narrowing of the Intertropical Convergence Zone and the Hadley Cell expansion under global warming, could be favoring the Saharan outflow to the Mediterranean Sea and Europe in detriment of transport to the Atlantic Ocean. The results also show that present-day Saharan air arrives at these regions at higher altitudes and in shorter timescales than decades ago. This is associated to the increase in surface heating conditions in the Sahara, 0.41 ± 0.02 °C dec^-1, that can inject air into windier upper atmospheric levels, thereby allowing higher and faster air transport. Our results suggest a change in the Saharan air outflow likely associated with global warming and with potentially significant implications for the temporal and spatial patterns of North African dust export.

High prevalence of urinary schistosomiasis in a desert population: results from an exploratory study around the Ounianga lakes in Chad

BACKGROUND

Researching a water-borne disease in the middle of the Sahara desert might not seem the most relevant concern. However, nomadic Sahelian pastoralists health concerns regarding their livestock and anecdotal reports about trematode infections of Fasciola spp. and Schistosoma spp. in desert-raised animals justified an exploratory study focusing on the lakes of Ounianga in Northern Chad. The aim was to test whether trematode parasites such as Schistosoma spp. occur in human populations living around the Sahara desert lakes of Ounianga Kebir and Ounianga Serir in northern Chad.

METHODS

The study was carried out in January 2019 and comprised of three components. First, a cross sectional survey based on a random sample drawn from the population to detect infections with S. haematobium and S. mansoni; second, focus group discussions exploring disease priorities, access to health and health seeking behaviour; and third, surveying water contact sites for intermediate host snails. Samples of trematode parasites and snails were confirmed on species level by molecular genetic methods. For parasitological and malacological surveys descriptive statistics were performed. Qualitative data analysis included the full review of all transcripts, followed by a descriptive and explorative thematic analysis.

RESULTS

Among 258 participants, the overall S. haematobium prevalence using urine filtration was 39.2% [95% confidence interval (CI): 33.5-45.1%], with 51.5% of the infected suffering from heavy infection. The intermediate host snail of S. haematobium (Bulinus truncatus) occurred at water contact sites near both study villages, revealing the potential for local transmission. Although a positive S. mansoni point-of-care circulating cathodic antigen (POC-CCA) test result was obtained from 8.6% (95% CI 5.7-12.8%) of the samples, no intermediate host snails of S. mansoni were found, and the relevance of S. mansoni remains uncertain. Qualitative findings underline the importance of morbidity caused by urinary schistosomiasis, and the lack of access to diagnostics and treatment as a major health concern.

CONCLUSIONS

This research revealed a high prevalence of urinary schistosomiasis in the population living around the lakes of Ounianga in the Sahara, a United Nations Educational, Scientific and Cultural Organization (UNESCO) world heritage site in Chad. Despite the high public health importance of the associated morbidity expressed by the population, there is no access to diagnostics and treatment. Further work is needed to develop and test a context-adapted intervention.

Pharmacological Investigations in Traditional Utilization of Alhagi maurorum Medik. in Saharan Algeria: In Vitro Study of Anti-Inflammatory and Antihyperglycemic Activities of Water-Soluble Polysaccharides Extracted from the Seeds

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi maurorum Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2). They were characterized using Fourier transform infrared, ¹H/¹³C Nuclear Magnetic Resonance, Gas Chromatography-Mass Spectrometry and Size Exclusion Chromatography coupled with Multi-Angle Light Scattering. The capacity of those fractions to inhibit α-amylase activity and thermally induced Bovine Serum Albumin denaturation were also investigated. WSPAM1 and WSPAM2 were galactomannans with a mannose/galactose ratio of 2.2 and 2.4, respectively. The SEC-MALLS analysis revealed that WSPAM1 had a molecular weight of 1.4 × 10⁶ Da. The investigations highlighted antinflammatory and antihyperglycemic effects in a dose-dependant manner of WSPAM1 and WSPAM2.

Endocrine, energy, and lipid status during parturition and early lactation in indigenous goats native to the Algerian Sahara

Background and Aim:

Goats are widely distributed in southwest Algeria. The Saharan goat is perfectly adapted to the harsh conditions of arid areas, and it is characterized by resistance to long photoperiod and reduced metabolic needs, allowing the survival of its offspring by maintaining lactation. Several studies have demonstrated that parturition and lactation are critical periods that induce hormone, energy, and lipid status changes in mammals. However, the relationship between the blood biochemical parameters of parturition control and lactation functions in the Algerian Saharan goat has not been thoroughly documented. Therefore, this study assesses hormone and metabolite levels during parturition and early lactation in Saharan goats reared in arid areas.

Materials and Methods:

Experiments were performed on 14 multiparous female goats, and blood samples were collected during parturition, 4 days postpartum (D1PP-D4PP), and during the first 12 weeks of lactation (W1-W12) to analyze prolactin, cortisol, glucose (GLU), total proteins (TP), cholesterol (CHO), triglycerides (TGs), total lipids (TL), low-density lipoproteins (LDLs), high-density lipoproteins (HDLs), and very LDLs (VLDLs).

Results:

Statistical data analysis revealed a significant (p<0.05) increase in plasma prolactin concentrations at W1 after parturition, reaching maximum values at W3 and W9, and remained high until W12 of lactation. Plasma cortisol levels were high at parturition, reaching two peaks at W3 and W9, and then decreased at W5, W7, and W12 of lactation. No significant changes were found in serum GLU levels during the first 7 weeks of lactation compared with parturition day; then, the levels became significantly (p<0.05) lower at W8, W11, and W12 of lactation. Plasma TP increased significantly (p<0.05) at D3PP, W1, and W4, then decreased significantly (p<0.05) at W8. In addition, this decrease coincided with that of GLU production. Serum CHO, TGs, TL, LDLs, and VLDLs, were low at parturition and high at D4PP and during the first 3 months of lactation. Furthermore, HDL levels were low at D3PP, 1^st, and 3^rd months and high at the 2^nd month of lactation.

Conclusion:

This study emphasized the impact of parturition and the 1^st weeks of lactation on endocrine and metabolic changes in indigenous goats living in the Algerian Sahara Desert. These results can be used to monitor and improve farming management and understand physiological adaptive strategies, mainly lactation function sustainability, of this goat living in marginal zones.

Drinking water provision and quality at the Sahrawi refugee camps in Tindouf (Algeria) from 2006 to 2016

Drinking water provision has been a constant challenge in the Sahrawi refugee camps, located in the desert near Tindouf (Algeria). The drinking water supply system is itself divided in three zones which pump groundwater from different deep aquifers. It is equipped with reverse osmosis plants and chlorination systems for treating water. The allocation of water supplied to the Saharawi refugees for human consumption in 2016 has been estimated at between 14 and 17 L/person/day on average. This supplied water volume is below recommended standards, and also below the strategic objective of the Sahrawi government (20 L/person/day). Yet the local groundwater resources are huge in comparison with estimated consumption, and hence there is great potential for increasing the supplied volume through effecting improvements in the supply system. The physico-chemical quality of the raw and supplied water between 2006 and 2016 has been assessed according to Algerian standards for human consumption. The raw water of two zones of the supply system presents a very high conductivity and high concentrations of chloride, nitrate, fluoride, sulfate, sodium, calcium, potassium and iodide concentrations of natural origin, which may entail health risks. The treatment of water in a reverse osmosis plant greatly improves its quality and osmosed water met the standards. However, the supply of osmosed and raw water needs to be combined in Zone 1, to avoid an excessive reduction in water volume, and the supplied raw water poses a risk to the health of the refugees. The present study provides an example of a drinking water supply system under extreme drought conditions and in the political and social conditions of a refugee camp. Furthermore, it establishes a reference for supplied water allocation and quality in the Sahrawi refugee camps.

Whole-genome sequencing of two Streptomyces strains isolated from the sand dunes of Sahara

BACKGROUND

Sahara is one of the largest deserts in the world. The harsh climatic conditions, especially high temperature and aridity lead to unique adaptation of organisms, which could be a potential source of new metabolites. In this respect, two Saharan soils from El Oued Souf and Beni Abbes in Algeria were collected. The bacterial isolates were selected by screening for antibacterial, antifungal, and enzymatic activities. The whole genomes of the two native Saharan strains were sequenced to study desert Streptomyces microbiology and ecology from a genomic perspective.

RESULTS

Strains Babs14 (from Beni Abbes, Algeria) and Osf17 (from El Oued Souf, Algeria) were initially identified by 16S rRNA sequencing as belonging to the Streptomyces genus. The whole genome sequencing of the two strains was performed using Pacific Biosciences Sequel II technology (PacBio), which showed that Babs14 and Osf17 have a linear chromosome of 8.00 Mb and 7.97 Mb, respectively. The number of identified protein coding genes was 6910 in Babs14 and 6894 in Osf17. No plasmids were found in Babs14, whereas three plasmids were detected in Osf17. Although the strains have different phenotypes and are from different regions, they showed very high similarities at the DNA level. The two strains are more similar to each other than either is to the closest database strain. The search for potential secondary metabolites was performed using antiSMASH and predicted 29 biosynthetic gene clusters (BGCs). Several BGCs and proteins were related to the biosynthesis of factors needed in response to environmental stress in temperature, UV light and osmolarity.

CONCLUSION

The genome sequencing of Saharan Streptomyces strains revealed factors that are related to their adaptation to an extreme environment and stress conditions. The genome information provides tools to study ecological adaptation in a desert environment and to explore the bioactive compounds of these microorganisms. The two whole genome sequences are among the first to be sequenced for the Streptomyces genus of Algerian Sahara. The present research was undertaken as a first step to more profoundly explore the desert microbiome.

Physical activity in Sahara Moroccan hemodialysis patients

OBJECTIVE

The evaluation of physical activity for chronic hemodialysis patients is a new approach for patient global care. The objective of this work is to evaluate the physical activity in chronic hemodialysis patients and identify the risk factors associated with reduced physical activity. This is a prospective study for 6 months including 150 chronic hemodialysis patients in the Guelmim-Oued Noun Regionin Moroccan Sahara. We use Baecke's survey, translated and validated in Arabic local language. The socio-demographic, clinical, and biological data were completed during the interrogation and from the medical records of the patients.

RESULTS

The mean age of our patients was 54.6 ± 16.4 years, with male predominance (59%). Most patients have a low education level and 60% were illiterate. Hypertension was found in 54% of our patients, diabetes in 39%, and cardiovascular disease in 10% of patients. Low Physical activity was associated with gender (OR = 4.05), age (OR = 1.03) and high education level (OR = 0.2). Our work has met the various pre-established objectives, however other more specific studies must be conducted to better characterize the profile of physical activity in chronic hemodialysis patients.

Assessment of the Nutritional Status, Diet and Intestinal Parasites in Hosted Saharawi Children

Since the early 1990s, Spanish humanitarian associations have welcomed Saharawi children from the refugee camps in Tindouf (Argelia). These children are the most affected by the lack of food, water, hygienic measures and health care. The main objective of this study was to analyze the anthropometric, nutritional and parasitological data of 38 Saharawi boys and girls (from 10 to 13 years old) under a holiday host program in the city of Valencia. Our results confirm that malnutrition and multiparasitism are highly frequent, so it is understood that living conditions in refugee camps continue to be precarious with a lack of proper hygiene and nutrition. Furthermore, biochemical alterations, lactose malabsorption and the risk of celiac disease, also detected in our study as a secondary objective, will complicate nutritional management and restoration of health. For this reason, sustainable feeding alternatives and interventions from a hygienic and nutritional point of view are proposed, emphasizing in an improvement in the education of parents and children.

Characterization of Bacteria on Aerosols From Dust Events in Dakar, Senegal, West Africa

We identify bacteria types on collected dust samples in Dakar Senegal, a region that experiences frequent Saharan dust events. We use classical techniques to identify bacteria types from dust samples. Seventy-seven bacteria types are identified from samples collected by spatula and the QuickTake® 30 air sampling pump. The dominant groups in the first batch of 51 bacteria (collected via deposition) are Micrococcus (33.33%), Bacillus (13.73%), Kytococcus (11.76%), Pseudomonas (9.80%), and Burkholderia (7.84%) and dominants in the second batch of 26 bacteria (collected with aerosol sampling vacuum pump): Pseudomonas (38.61%), Burkholderia (26.92%), Micrococcus (11.54%), and Brucella spp (7.69%). These bacteria are found in earlier studies from desert sources and can potentially cause respiratory diseases to exposed populations. Future work will use molecular methods is necessary to search for additional pathogens, including viruses on dust aerosols.

Round-trip across the Sahara: Afrotropical Painted Lady butterflies recolonize the Mediterranean in early spring

The Palearctic-African migratory circuit has been typically associated with birds. Very few insects are known to endure annual trans-Saharan circuits, but the Painted Lady butterfly (Vanessa cardui) is an exception. While it was demonstrated that this species massively migrates from Europe to the Afrotropics during the autumn, the existence of a reverse migration from the Afrotropics to Europe in the early spring remains hypothetical. Here, we analysed wing stable hydrogen isotope values (δ²H) of V. cardui migrants collected from February to April across the circum-Mediterranean region. We assessed their region of natal origin by comparing their wing isotope signature predicted δ²H values (isoscape). The results unambiguously demonstrate a sub-Saharan origin for many individuals, especially those collected in February, representing the first tangible evidence for a reverse northwards trans-Saharan migration in spring. This work supports the view that the Afrotropics (mostly exploited from September to February) is key in the V. cardui Palearctic-African population dynamics. This species relies on both temperate and tropical habitats to complete their multigenerational cycle, an unprecedented adaptation for butterflies and for most migratory insects. Such a migratory circuit has strong parallelisms with those of migratory birds.

Oasis Malaria, Northern Mauritania1

A malaria survey was conducted in Atar, the northernmost oasis city in Mauritania, during 2015–2016. All febrile patients in whom malaria was suspected were screened for malaria by using rapid diagnostic testing and microscopic examination of blood smears and later confirmed by PCR. Of 453 suspected malaria cases, 108 (23.8%) were positive by rapid diagnostic testing, 154 (34.0%) by microscopic examination, and 162 (35.7%) by PCR. Malaria cases were observed throughout the year and among all age groups. Plasmodium vivax was present in 120/162 (74.1%) cases, P. falciparum in 4/162 (2.4%), and mixed P. falciparum–P. vivax in 38/162 (23.4%). Malaria is endemic in northern Mauritania and could be spreading farther north in the Sahara, possibly because of human-driven environmental changes. Further entomologic and parasitologic studies and monitoring are needed to relate these findings to major Anopheles mosquito vectors and to design and implement strategies for malaria prevention and control.

Multiple radiations of spiny mice (Rodentia: Acomys) in dry open habitats of Afro-Arabia: evidence from a multi-locus phylogeny

Background

Spiny mice of the genus Acomys are distributed mainly in dry open habitats in Africa and the Middle East, and they are widely used as model taxa for various biological disciplines (e.g. ecology, physiology and evolutionary biology). Despite their importance, large distribution and abundance in local communities, the phylogeny and the species limits in the genus are poorly resolved, and this is especially true for sub-Saharan taxa. The main aims of this study are (1) to reconstruct phylogenetic relationships of Acomys based on the largest available multilocus dataset (700 genotyped individuals from 282 localities), (2) to identify the main biogeographical divides in the distribution of Acomys diversity in dry open habitats in Afro-Arabia, (3) to reconstruct the historical biogeography of the genus, and finally (4) to estimate the species richness of the genus by application of the phylogenetic species concept.

Results

The multilocus phylogeny based on four genetic markers shows presence of five major groups of Acomys called here subspinosus, spinosissimus, russatus, wilsoni and cahirinus groups. Three of these major groups (spinosissimus, wilsoni and cahirinus) are further sub-structured to phylogenetic lineages with predominantly parapatric distributions. Combination of alternative species delimitation methods suggests the existence of 26 molecular operational taxonomic units (MOTUs), potentially corresponding to separate species. The highest genetic diversity was found in Eastern Africa. The origin of the genus Acomys is dated to late Miocene (ca. 8.7 Ma), when the first split occurred between spiny mice of eastern (Somali-Masai) and south-eastern (Zambezian) savannas. Further diversification, mostly in Plio-Pleistocene, and the current distribution of Acomys were influenced by the interplay of global climatic factors (e.g., Messinian salinity crisis, intensification of Northern Hemisphere glaciation) with local geomorphology (mountain chains, aridity belts, water bodies). Combination of divergence dating, species distribution modelling and historical biogeography analysis suggests repeated “out-of-East-Africa” dispersal events into western Africa, the Mediterranean region and Arabia.

Conclusions

The genus Acomys is very suitable model for historical phylogeographic and biogeographic reconstructions of dry non-forested environments in Afro-Arabia. We provide the most thorough phylogenetic reconstruction of the genus and identify major factors that influenced its evolutionary history since the late Miocene. We also highlight the urgent need of integrative taxonomic revision of east African taxa.

Electronic supplementary material

The online version of this article (10.1186/s12862-019-1380-9) contains supplementary material, which is available to authorized users.

Assessment of drug resistance associated genetic diversity in Mauritanian isolates of Plasmodium vivax reveals limited polymorphism

Background

Plasmodium vivax is the predominant malaria species in northern Mauritania. Molecular data on P. vivax isolates circulating in West Africa are scarce. The present study analysed molecular markers associated with resistance to antifolates (Pvdhfr and Pvdhps), chloroquine (Pvmdr1), and artemisinin (Pvk12) in P. vivax isolates collected in two cities located in the Saharan zone of Mauritania.

Methods

Blood samples were obtained from P. vivax-infected patients recruited for chloroquine therapeutic efficacy study in 2013 and febrile patients spontaneously consulting health facilities in Nouakchott and Atar in 2015–2016. Fragments of Pvdhfr (codons 13, 33, 57, 58, 61, 117, and 174), Pvdhps (codons 382, 383, 512, 553, and 585), Pvmdr1 (codons 976 and 1076) and Pvk12 (codon 552) genes were amplified by PCR and sequenced.

Results

Most of the isolates in Nouakchott (126/154, 81.8%) and Atar (44/45, 97.8%) carried the wild-type Pvdhfr allelic variant (IPFSTSI). In Nouakchott, all mutants (28/154; 18.2%) had double Pvdhfr mutations in positions 58 and 61 (allelic variant IPFRMSI), whereas in Atar only 1 isolate was mutant (S117N, allelic variant IPFSTNI). The wild-type Pvdhps allelic variant (SAKAV) was found in all tested isolates (Nouakchott, n = 93; Atar, n = 37). Few isolates in Nouakchott (5/115, 4.3%) and Atar (3/79, 3.8%) had the mutant Pvmdr1 allele 976F or 1076L, but not both, including in pre-treatment isolates obtained from patients treated successfully with chloroquine. All isolates (59 in Nouakchott and 48 in Atar) carried the wild-type V552 allele in Pvk12.

Conclusions

Polymorphisms in Pvdhfr, Pvdhps, Pvmdr1, and Pvk12 were limited in P. vivax isolates collected recently in Nouakchott and Atar. Compared to the isolates collected in Nouakchott in 2007–2009, there was no evidence for selection of mutants. The presence of one, but not both, of the two potential markers of chloroquine resistance in Pvmdr1 in pre-treatment isolates did not influence the clinical outcome, putting into question the role of Pvmdr1 mutant alleles 976F and 1076L in treatment failure. Molecular surveillance is an important component of P. vivax malaria control programme in the Saharan zone of Mauritania to predict possible emergence of drug-resistant parasites.

Pollen metabarcoding as a tool for tracking long-distance insect migrations

Insects account for a large portion of Earth's biodiversity and are key players for ecosystems, notably as pollinators. While insect migration is suspected to represent a natural phenomenon of major importance, remarkably little is known about it, except for a few flagship species. The reason for this situation is mainly due to technical limitations in the study of insect movement. Here, we propose using metabarcoding of pollen carried by insects as a method for tracking their migrations. We developed a flexible and simple protocol allowing efficient multiplexing and not requiring DNA extraction, one of the most time-consuming part of metabarcoding protocols, and apply this method to the study of the long-distance migration of the butterfly Vanessa cardui, an emerging model for insect migration. We collected 47 butterfly samples along the Mediterranean coast of Spain in spring and performed metabarcoding of pollen collected from their bodies to test for potential arrivals from the African continent. In total, we detected 157 plant species from 23 orders, most of which (82.8%) were insect-pollinated. Taxa present in Africa-Arabia represented 73.2% of our data set, and 19.1% were endemic to this region, strongly supporting the hypothesis that migratory butterflies colonize southern Europe from Africa in spring. Moreover, our data suggest that a northwards trans-Saharan migration in spring is plausible for early arrivals (February) into Europe, as shown by the presence of Saharan floristic elements. Our results demonstrate the possibility of regular insect-mediated transcontinental pollination, with potential implications for ecosystem functioning, agriculture and plant phylogeography.

Short-term effects of desert and non-desert PM10 on mortality in Sicily, Italy

BACKGROUND

Increased PM₁₀ concentrations are commonly observed during Saharan dust advections. Limited epidemiological evidence suggests that PM₁₀ from anthropogenic and desert sources increase mortality. We aimed to evaluate the association between source-specific PM₁₀ (non-desert and desert) and cause-specific mortality in Sicily during 2006-2012 period.

METHODS

Daily PM₁₀ concentrations at 1-km² were estimated in Sicily using satellite-based data, fixed monitors and land use variables. We identified Saharan dust episodes using meteorological models, back-trajectories, aerosol maps, and satellite images. For each dust day, we estimated desert and non-desert PM₁₀ concentrations. We applied a time-series approach on 390 municipalities of Sicily to estimate the association between PM₁₀ (non-desert and desert) and daily cause-specific mortality.

RESULTS

33% of all days were affected by Saharan dust advections. PM₁₀ concentrations were 8 μg/m³ higher during dust days compared to other days. We found positive associations of both non-desert and desert PM₁₀ with cause-specific mortality. We estimated percent increases of risk (IR%) of non-accidental mortality equal to 2.3% (95% Confidence Interval [CI]: 1.4, 3.1) and 3.8% (3.2, 4.4), per 10 μg/m³ increases in non-desert and desert PM₁₀ at lag 0-5, respectively. We also observed significant associations with cardiovascular (2.4% [1.3, 3.4] and 4.5% [3.8, 5.3]) and respiratory mortality (8.1% [6.8, 9.5], and 6.3% [5.4, 7.2]). We estimated higher effects during April-September, with IR% = 4.4% (3.2, 5.7) and 6.3% (5.4, 7.2) for non-desert and desert PM₁₀, respectively.

CONCLUSIONS

Our results confirm previous evidence of harmful effects of desert PM₁₀ on non-accidental and cardio-respiratory mortality, especially during the warm season.

WRF 1960-2014 Winter Season Simulations of Particulate Matter in the Sahel: Implications for Air Quality and Respiratory Health

We use the Weather Research and Forecast model using the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) dust module (WRF-CHEM) to simulate the particulate matter (PM) variations in the Sahel during the winter seasons (January-March) of 1960-2014. Two simulations are undertaken where the direct aerosol feedback is turned off, and only transport is considered and where the direct aerosol feedback is turned on. We find that simulated Sahelian PM10 and PM2.5 concentrations were lower in the 1960s and after 2003 and higher during the period between 1988 and 2002. Higher Sahelian PM10 concentrations are due to stronger winds between the surface and 925 hPa over the Sahara, which transport dust into the Sahel. Negative PM10 concentration anomalies are found over the Bodele Depression and associated with weaker 925 wind anomalies after 1997 through 2014. Further west, positive PM10 concentration anomalies are found across the Adrar Plateau in the Sahara and responsible for dust transport to the Western Sahel. The North Atlantic Oscillation (NAO) is positively correlated to Sahelian dust concentrations especially during the periods of 1960-1970 and 1988-2002. The temporal/spatial patterns of PM10 concentrations have significant respiratory health implications for inhabitants of the Sahel.

Use of quantitative ultrasound as bone mineral density evaluation in an Italian female population living with HIV: A real-life experience

This is a multicenter cross-sectional study where we aimed to detect the rate of osteopenia/osteoporosis in an HIV female population (WLWHIV) by means of "heel quantitative ultrasound" (QUS) measurement. We enrolled 273 patients, mean age 48.1 years, 36% menopausal, 96% on combination antiretroviral therapy (cART). Calcaneal measure of bone mass index by QUS revealed osteopenia and osteoporosis in 76 (27.8%) and 16 (5.9%) WLWHIV. Our data underline the correlation between low QUS parameters and traditional risk factors for osteoporosis rather than with cART exposure, thus suggesting the crucial importance of detection and correction of traditional risk factors for osteoporosis in WLWHIV.

Long-distance autumn migration across the Sahara by painted lady butterflies: exploiting resource pulses in the tropical savannah

The painted lady, Vanessa cardui, is a migratory butterfly that performs an annual multi-generational migration between Europe and North Africa. Its seasonal appearance south of the Sahara in autumn is well known and has led to the suggestion that it results from extremely long migratory flights by European butterflies to seasonally exploit the Sahel and the tropical savannah. However, this possibility has remained unproven. Here, we analyse the isotopic composition of butterflies from seven European and seven African countries to provide new support for this hypothesis. Each individual was assigned a geographical natal origin, based on its wing stable hydrogen isotope (δ²H_w) value and a predicted δ²H_w basemap for Europe and northern Africa. Natal assignments of autumn migrants collected south of the Sahara confirmed long-distance movements (of 4000 km or more) starting in Europe. Samples from Maghreb revealed a mixed origin of migrants, with most individuals with a European origin, but others having originated in the Sahel. Therefore, autumn movements are not only directed to northwestern Africa, but also include southward and northward flights across the Sahara. Through this remarkable behaviour, the productive but highly seasonal region south of the Sahara is incorporated into the migratory circuit of V. cardui.

First checklist of the fruit flies of Morocco, including new records (Diptera, Tephritidae)

The first checklist of the Tephritidae of Morocco, containing 59 species, is presented here. Out of 38 species collected during the present project, three (Campiglossa martii (Becker, 1908), Tephritis divisa (Rondani, 1871), and Terellia sp. near longicauda) present new records for North Africa, and ten (Carpomya incompleta (Becker, 1903), Chaetorellia conjuncta (Becker, 1913), Chetostoma curvinerve Rondani, 1856, Dacus frontalis (Becker, 1922), D. longistylus (Wiedemann, 1830), Dioxyna sororcula (Wiedemann, 1830), Ensina sonchi (Linnaeus, 1767), Myopites inulaedyssentericae Blot, 1827, M. stylatus Fabricius, 1794, and Tephritis vespertina (Loew, 1844)) are new for Morocco.

Piebald Camels

Animal breeds are the diverse outcome of the thousands-year-long process of livestock domestication. Many of these breeds are piebald, resulting from the artificial selection by pastoralists of animals bearing a genetic condition known as leucism, and selected for their productive, behavioural, or aesthetical traits. Piebald dromedary camels have not been studied or discussed before, and their same existence is often overlooked. Based on fieldwork in Western Sahara, direct observations across Northern and East Africa and the Middle East, and a literature review, we address the morphological and behavioural traits, geographical distribution, taxonomy, and material and cultural importance of piebald (painted) camels. They are a hundreds-year-old camel breed used for caravans, as mounts, and for aesthetical and cultural reasons across Sudan, Niger, Mali, Mauritania, Western Sahara, and Morocco. While they are increasingly bred out of a pastoral context for tourism and entertainment in the Canary Islands, mainland Europe, and the USA, in part of their original African range, piebald camels are under threat due to wars, droughts, and demise of pastoral livelihoods. More research is needed about these 'beautiful and dignified' animals.

The role of Nucularia perrinii Batt. (Chenopodiaceae) in the camel-based Sahrawi social-ecological system

BACKGROUND

Pastoral social-ecological systems (SESs) are adaptive and complex systems rooted in the extensive exploitation of forage plants for livestock-based livelihoods and culture. There are species and relations that are foundational to the existence of these SESs. Nucularia perrinii Batt. (Chenopodiaceae) is an endemic halophyte plant of central and western Sahara seldom cited in the scientific literature. The objective of this study was to investigate the role of this plant in the SES of the Sahrawi camel nomads of Western Sahara.

METHODS

The data analyzed were collected in the Sahrawi refugee camps of Algeria and in Western Sahara between 2006 and 2010. Fieldwork included semi-structured (n = 38) and retrospective (n = 12) interviews with Sahrawi refugees, nomads, and camel owners about N. perrinii and associated topics (e.g. distribution, importance for camels, camel diseases, associated grazing practices, other forage plants, etc.).

RESULTS

Askaf, as the Sahrawi call the plant, is crucial to camels' survival, providing salts and water even during dry spells. It holds a pivotal role in the Sahrawi culture, defining the geographical boundaries of the Sahrawi SES and relating the grazing territory with the taste it gives to camel milk, which support the inclusion of askaf as a main element of Sahrawi cultural identity.

CONCLUSIONS

We argue that N. perrinii ties the ecology of the western Sahara desert with camel husbandry and associated livelihoods, and further with the culture and worldview of the Sahrawi nomads. We stress the keystone role that some forage plants may have in extensive pastoral SESs worldwide.

Health and sanitary status in 1970 of Tubu nomads dwelling in Northeastern Niger

BACKGROUND

The Tubu are nomadic people who live in remote parts of the central Sahara, primarily in the Tibesti massif (Chad), and in both Northeastern Niger and Southern Libya. No data about the Tubu's health and sanitary status are currently available.

METHODS

In 1970, the "Mission Anthropologique Belge au Niger" (MABN) investigated a Tubu tribe named Broaya that lived on the northeastern rim of the Tenere desert. One hundred and fifty-one adult volunteers were investigated. The environmental fauna of medical importance was also studied.

RESULTS

Albeit 43 year-old, these results have not been previously published. The estimated age of death for fathers was approximately 56 years, and that for mothers was 60 years. The overall perinatal mortality rate was 232%, the overall infant mortality rate was 153%, and the overall child mortality rate was 99%. The physical examination found 6 cases of blindness (4.0%). Five subjects presented with an elevated blood pressure (3.3%), and 5 (3.3%) displayed an abnormal thoracic auscultation evocative of tuberculosis or of an acute lung infection. In the field, no blood-fluke eggs were found in the urine samples. The blood thin films and stool samples were preserved then subsequently examined in Toulouse. The search for blood parasites was negative. Three subjects (2%) passed E. histolytica/E. dispar cysts in stools, 16 (10.6%) were parasitized with Giardia sp. and 4 (2.65%) were parasitized with Hymenolepis nana. Two specimens of scorpions captured in the camp were subsequently identified as belonging to the harmful genus Androctonus or Leiurus. An investigation into the freshwater fauna was conducted in the marshy ponds surrounding the ghost city of Djado, and no intermediate snail hosts for schistosomiasis haematobium were found. Larvae and nymphs, of Anopheles hispaniola and of An. multicolor, which are not efficient vectors for malaria, were collected.

CONCLUSIONS

Infection-related blindness and trachoma, along with acute pulmonary infections and probably tuberculosis were the major health burden in this tribe. The harsh dry and hot climate may explain the low prevalence of soil-transmitted protozoan diseases or helminthiases.

A new species of the rare buthid scorpion genus Lissothus Vachon, 1948 from Central Algeria (Scorpiones, Buthidae)

Taxonomic considerations are given for the genus Lissothus Vachon, 1948 (Scorpiones, Buthidae). Two species are currently known, Lissothus bernardi Vachon, 1948 from Libya and Lissothus occidentalis Vachon, 1950 from Mauritania. In this contribution, a new species, Lissothus chaambi sp. n., is described from the desert of Central Algeria. The new species is most closely related to L. bernardi. The geographical distribution of the genus is discussed.

The formation of a large summertime Saharan dust plume: Convective and synoptic-scale analysis

Haboobs are dust storms produced by the spreading of evaporatively cooled air from thunderstorms over dusty surfaces and are a major dust uplift process in the Sahara. In this study observations, reanalysis, and a high-resolution simulation using the Weather Research and Forecasting model are used to analyze the multiscale dynamics which produced a long-lived (over 2 days) Saharan mesoscale convective system (MCS) and an unusually large haboob in June 2010. An upper level trough and wave on the subtropical jet 5 days prior to MCS initiation produce a precipitating tropical cloud plume associated with a disruption of the Saharan heat low and moistening of the central Sahara. The restrengthening Saharan heat low and a Mediterranean cold surge produce a convergent region over the Hoggar and Aïr Mountains, where small convective systems help further increase boundary layer moisture. Emerging from this region the MCS has intermittent triggering of new cells, but later favorable deep layer shear produces a mesoscale convective complex. The unusually large size of the resulting dust plume (over 1000 km long) is linked to the longevity and vigor of the MCS, an enhanced pressure gradient due to lee cyclogenesis near the Atlas Mountains, and shallow precipitating clouds along the northern edge of the cold pool. Dust uplift processes identified are (1) strong winds near the cold pool front, (2) enhanced nocturnal low-level jet within the aged cold pool, and (3) a bore formed by the cold pool front on the nocturnal boundary layer.

Unravelling biodiversity, evolution and threats to conservation in the Sahara-Sahel

Deserts and arid regions are generally perceived as bare and rather homogeneous areas of low diversity. The Sahara is the largest warm desert in the world and together with the arid Sahel displays high topographical and climatic heterogeneity, and has experienced recent and strong climatic oscillations that have greatly shifted biodiversity distribution and community composition. The large size, remoteness and long-term political instability of the Sahara-Sahel, have limited knowledge on its biodiversity. However, over the last decade, there have been an increasing number of published scientific studies based on modern geomatic and molecular tools, and broad sampling of taxa of these regions. This review tracks trends in knowledge about biodiversity patterns, processes and threats across the Sahara-Sahel, and anticipates needs for biodiversity research and conservation. Recent studies are changing completely the perception of regional biodiversity patterns. Instead of relatively low species diversity with distribution covering most of the region, studies now suggest a high rate of endemism and larger number of species, with much narrower and fragmented ranges, frequently limited to micro-hotspots of biodiversity. Molecular-based studies are also unravelling cryptic diversity associated with mountains, which together with recent distribution atlases, allows identifying integrative biogeographic patterns in biodiversity distribution. Mapping of multivariate environmental variation (at 1 km × 1 km resolution) of the region illustrates main biogeographical features of the Sahara-Sahel and supports recently hypothesised dispersal corridors and refugia. Micro-scale water-features present mostly in mountains have been associated with local biodiversity hotspots. However, the distribution of available data on vertebrates highlights current knowledge gaps that still apply to a large proportion of the Sahara-Sahel. Current research is providing insights into key evolutionary and ecological processes, including causes and timing of radiation and divergence for multiple taxa, and associating the onset of the Sahara with diversification processes for low-mobility vertebrates. Examples of phylogeographic patterns are showing the importance of allopatric speciation in the Sahara-Sahel, and this review presents a synthetic overview of the most commonly hypothesised diversification mechanisms. Studies are also stressing that biodiversity is threatened by increasing human activities in the region, including overhunting and natural resources prospection, and in the future by predicted global warming. A representation of areas of conflict, landmines, and natural resources extraction illustrates how human activities and regional insecurity are hampering biodiversity research and conservation. Although there are still numerous knowledge gaps for the optimised conservation of biodiversity in the region, a set of research priorities is provided to identify the framework data needed to support regional conservation planning.

A study of the relict fish fauna of northern Chad, with the first records of a polypterid and a poeciliid in the Sahara desert

Seventeen species and sub-species of fishes belonging to four families (Cyprinidae, Clariidae, Aplocheilidae, Cichlidae) were known to occur in perennial bodies of water in the Sahara desert. The study of fishes collected in Lake Boukou near Ounianga Serir (Borkou, northern Chad) shows, for the first time, the occurrence in the Sahara desert of relict populations of Polypterus senegalus (Polypteridae) and Poropanchax normani (Poeciliidae). The Cichlidae Tilapia zilli was also collected in this lake. With these new records, the relict fish fauna currently known in lakes and gueltas of the Borkou plateaus comprises six species. In the Ennedi Mountains, where the specific status of Barbus populations was unclear, B. macrops was collected in Bachikere guelta. The toad Amietophrynus regularis was collected in Ounianga Kebir.

Population genetics of Mediterranean and Saharan olives: geographic patterns of differentiation and evidence for early generations of admixture

BACKGROUND AND AIMS

The olive (Olea europaea subsp. europaea) was domesticated in the Mediterranean area but its wild relatives are distributed over three continents, from the Mediterranean basin to South Africa and south-western Asia. Recent studies suggested that this crop originated in the Levant while a secondary diversification occurred in most westward areas. A possible contribution of the Saharan subspecies (subsp. laperrinei) has been highlighted, but the data available were too limited to draw definite conclusions. Here, patterns of genetic differentiation in the Mediterranean and Saharan olives are analysed to test for recent admixture between these taxa.

METHODS

Nuclear microsatellite and plastid DNA (ptDNA) data were compiled from previous studies and completed for a sample of 470 cultivars, 390 wild Mediterranean trees and 270 Saharan olives. A network was reconstructed for the ptDNA haplotypes, while a Bayesian clustering method was applied to identify the main gene pools in the data set and then simulate and test for early generations of admixture between Mediterranean and Saharan olives.

KEY RESULTS

Four lineages of ptDNA haplotypes are recognized: three from the Mediterranean basin and one from the Sahara. Only one haplotype, primarily distributed in the Sahara, is shared between laperrinei and europaea. This haplotype is detected once in 'Dhokar', a cultivar from the Maghreb. Nuclear microsatellites show geographic patterns of genetic differentiation in the Mediterranean olive that reflect the primary origins of cultivars in the Levant, and indicate a high genetic differentiation between europaea and laperrinei. No first-generation hybrid between europaea and laperrinei is detected, but recent, reciprocal admixture between Mediterranean and Saharan subspecies is found in a few accessions, including 'Dhokar'.

CONCLUSIONS

This study reports for the first time admixture between Mediterranean and Saharan olives. Although its contribution remains limited, Laperrine's olive has been involved in the diversification of cultivated olives.