Reference Collection Research Articles

The potential of polymer for enhanced oil recovery process on oil refinery: A literature research

The objective of this research is to obtain evidence that polymer can be utilized as injection fluid in Enhanced Oil Recovery process. Polymer is one of chemical compounds in Chemical Enhanced Oil Recovery (CEOR). The method utilized in this research is reference collection regarding Enhanced Oil Recovery which further observed and reviewed, especially the ones connected with polymer utilization as injection fluid. Polymer injection is a method conducted after primary and secondary recoveries processes. The clearest and most significant mechanism of polymer application is to improve sweep efficiency by decreasing thickness level and improving water injection profile. Polymer injection is a tertiary recovery step, conducted after oil can no longer be produced although the capacity only reaches 60%. This means that there is still 40% of total capacity yet to be produced. This polymer injection is commonly utilized to obtain remaining oil reserve because of its relatively simple application, low cost, and able to produce a relatively large volume of oil reserve.

Timorese archaeobotany: An anthracological pilot study at the late Holocene Lepu-Kina rockshelter, Atauro Island, East Timor

This paper details an anthracological pilot study for the Lepu-Kina rockshelter site (AT-7), located on Atauro Island, East Timor and considers the implications of the preliminary results for the archaeology of the region. Archaeological wood charcoal analysis can reveal aspects of fuel selection, human landscape modifications and management of vegetal resources. The difficulties inherent in tropical archaeobotany have, however, constrained anthracological research in Island Southeast Asia. This study is therefore principally an attempt to assess the potential for future anthracological investigations to address archaeological questions related to vegetation resource uses and horticultural practices in Island Southeast Asia. Results reveal that the occupants of the Lepu-Kina rockshelter 2500 years ago had access to abundant semi-evergreen tropical forests and savannah. The presence of Artocarpus, identified as either breadnut or breadfruit (A. cf. altilis/camansi) is also recorded. These results confirm that a more expansive anthracological investigation of the Lepu-Kina rockshelter, accompanied by a local or regional reference collection and wood anatomy resource, has significant potential to expand on these initial observations.

Nutritional Constituents and Food Culture of Early Humans in Dry Zone: Based on Faunal Remain Analysis of Rajagala Mahalena Excavation Site

Zooarchaeological specimens are rich in both biological and cultural data and the study of faunal assemblages from archaeological sites provide important information about the socio-cultural lifestyle of early humans. However, the food and nutrition of early humans, their dietary patterns, the nutrients they received, and the sufficiency of nutrients were not much discussed in relation to faunal remain analyses. Therefore, this research attempted to find out the food consumption and its nutritional constituents of Homo sapiens sapiens that lived in dry zone areas through faunal remain analysis. The faunal remains excavated in 2018 and 2019 from Rajagala Mahalena excavation site, located in Ampara District in Sri Lanka were used for this study. The carefully washed, dried, sorted and labelled faunal specimens were used for the analysis. Remains from all contexts were collected from the excavation store and off-site methodology was used for the identification of remains by comparing the reference collection with excavated bone collection. A comparative methodology was utilized based on the nutritional values and the other values of food, specially based on animal meat to get the nutritional value which may be provided by the bone samples. Among the faunal assemblages collected, nearly 34 species belonged to six major taxonomic classes representing Mammalia, Reptilia, Aves, Pisces Gastropoda and Bivalvia. Large animals with more meat such as wild cats, leopards, buffaloes, deer, wild pigs etc. can be considered as the traditional sources of Proteins. Reptile species such as land monitors, hard-shelled and soft-shelled tortoises are also rich in proteins and fat which give more strength to human body, in addition to fish, birds were also included in the diet. The results show that hunting-gathering subsistence pattern and the environment they occupied were challenging and required lot of energy to maintain their lives. It is evident that proteins and fats provided higher calories and contain minerals and vitamins which are essential for brain development, to build tissues, bones and better functioning of skeletal joints. The quantitative analysis of the remains has given information on animal food preference of early humans and the role of animals in food and foraging economics of early human population.

Revisiting metric sex estimation of burnt human remains via supervised learning using a reference collection of modern identified cremated individuals (Knoxville, USA).

This study aims to increase the rate of correctly sexed calcined individuals from archaeological and forensic contexts. This is achieved by evaluating sexual dimorphism of commonly used and new skeletal elements via uni- and multi-variate metric trait analyses. Twenty-two skeletal traits were evaluated in 86 individuals from the William M. Bass donated cremated collection of known sex and age-at-death. Four different predictive models, logistic regression, random forest, neural network, and calculation of population specific cut-off points, were used to determine the classification accuracy (CA) of each feature and several combinations thereof. An overall CA of ≥ 80% was obtained for 12 out of 22 features (humerus trochlea max., and lunate length, humerus head vertical diameter, humerus head transverse diameter, radius head max., femur head vertical diameter, patella width, patella thickness, and talus trochlea length) using univariate analysis. Multivariate analysis showed an increase of CA (≥ 95%) for certain combinations and models (e.g., humerus trochlea max. and patella thickness). Our study shows metric sexual dimorphism to be well preserved in calcined human remains, despite the changes that occur during burning. Our study demonstrated the potential of machine learning approaches, such as neural networks, for multivariate analyses. Using these statistical methods improves the rate of correct sex estimations in calcined human remains and can be applied to highly fragmented unburnt individuals from both archaeological and forensic contexts.

Reconstructing freshwater fishing seasonality in a neotropical savanna: First application of swamp eel (Synbranchus marmoratus) sclerochronology to a pre-Columbian Amazonian site (Loma Salvatierra, Bolivia)

Sclerochronology is a method used to estimate the season of death (season of capture) of archaeological individuals based on a modern growth model. This method has been increasingly accepted in South America and has mainly been applied to coastal archaeological sites (on the Atlantic and Pacific Oceans). This is the first time that this method has been applied to a freshwater species, the marbled swamp eel (Synbranchus marmoratus), in archaeology. Excavations undertaken at Loma Salvatierra, a human-built platform located in the Bolivian Amazon and occupied from 500 until 1400 CE, have yielded 111 zooarchaeological vertebrae of the marbled swamp eel, which is one of the most widely distributed species recovered in South American continental archaeological sites. In order to estimate the fishing season for these archaeological individuals, we developed a modern osteological reference collection, made up of 61 specimens with known capture dates sampled monthly over a one-year period, about 60 km from Loma Salvatierra. The vertebrae present periodic growth patterns with a succession of dark and light bands alternately. Consequently, the vertebrae are a reliable basis for the estimation of the marbled swamp eel fishing season. The analysis of the marginal increments of vertebrae in present-day fish allowed us to elaborate a modern growth model showing that the seasonal growth of the marbled swamp eel is related to the hydrological cycle, whereby the fast growth period coincides with the onset of rainfall in the region. On the basis of this modern-based model, the analysis of zooarchaeological vertebrae demonstrates that fish were captured over several seasons. Demonstrating that human groups occupied villages year-round does not mean that they were not mobile but shows year-round fishing in the savanna. This year-round fishing practice raises questions concerning the generalized idea of fishing as an exclusively dry-season activity. As wild resources are generally seasonal, the evidence of the year-round fishing of swamp eels might suggest year-round fishing at Loma Salvatierra and contributes to the understanding of late-Holocene mobility patterns in pre-Columbian times.

An examination of histomorphometric relationships in the anterior and posterior human femoral cortex.

Static cortical bone histomorphometry utilised in forensic age-at-death estimation generally examines only the anterior femoral mid-shaft, as biomechanical strain at the posterior femur is thought to result in increased bone remodelling, osteon density and adversely affect age-at-death estimates. As osteon density increases there is a corresponding decrease in geometric variables, such as osteon area and Haversian canal diameter. The present study tests whether the inverse relationship between osteon density and osteon geometry is reflected in a modern documented Australian sample, and if this relationship differs between the anterior and posterior femoral mid-shaft. The study sample comprises 215 femoral microradiographs (117♂ 98♀) of recorded age (18‒97years) from the Melbourne Femur Reference Collection (MFRC). The following variables were measured in Image J across six 1mm2 regions of interest (ROIs) from the anterior and posterior; mean intact and fragmentary secondary osteon count, osteon population density, osteon and Haversian canal area, perimeter, and diameter. Osteon area was positively correlated with Haversian canal size and shape metrics, and negatively correlated with osteon density. Chronological age was significantly correlated with most variables. There were significant between-group effects between the youngest (18‒34years) and all other age groups (35‒49, 50-74 and 75 + years) for both regions. Our findings support an increased rate of remodelling associated with decreases in osteon geometry in the anterior and posterior femur. Future studies should examine static osteon histomorphometry using anterior and posterior measurements in larger samples of documented age and sex.

Haldor Topsoe's catalyst reduces emissions from new nitric acid plant in Greece

Sclerochronology is a method used to estimate the season of death (season of capture) of archaeological individuals based on a modern growth model. This method has been increasingly accepted in South America and has mainly been applied to coastal archaeological sites (on the Atlantic and Pacific Oceans). This is the first time that this method has been applied to a freshwater species, the marbled swamp eel (Synbranchus marmoratus), in archaeology. Excavations undertaken at Loma Salvatierra, a human-built platform located in the Bolivian Amazon and occupied from 500 until 1400 CE, have yielded 111 zooarchaeological vertebrae of the marbled swamp eel, which is one of the most widely distributed species recovered in South American continental archaeological sites. In order to estimate the fishing season for these archaeological individuals, we developed a modern osteological reference collection, made up of 61 specimens with known capture dates sampled monthly over a one-year period, about 60 km from Loma Salvatierra. The vertebrae present periodic growth patterns with a succession of dark and light bands alternately. Consequently, the vertebrae are a reliable basis for the estimation of the marbled swamp eel fishing season. The analysis of the marginal increments of vertebrae in present-day fish allowed us to elaborate a modern growth model showing that the seasonal growth of the marbled swamp eel is related to the hydrological cycle, whereby the fast growth period coincides with the onset of rainfall in the region. On the basis of this modern-based model, the analysis of zooarchaeological vertebrae demonstrates that fish were captured over several seasons. Demonstrating that human groups occupied villages year-round does not mean that they were not mobile but shows year-round fishing in the savanna. This year-round fishing practice raises questions concerning the generalized idea of fishing as an exclusively dry-season activity. As wild resources are generally seasonal, the evidence of the year-round fishing of swamp eels might suggest year-round fishing at Loma Salvatierra and contributes to the understanding of late-Holocene mobility patterns in pre-Columbian times.

Food Habits of the Macaronesian Sparrowhawk (Accipiter nisus granti) on Madeira

This work was carried out under the project LIFE12 NAT/PT/000402. We thank everyone (mainly volunteers) who contributed to this study. The Natural History Museum of Funchal permitted us to use its reference collection. The study complied with the current laws of Portugal. The manuscript was edited by Guido Jones, currently funded by the Cabildo de Tenerife, under the TFinnova Programme supported by MEDI and FDCAN Found.

DNA barcodes for UK freshwater arthropod species: coverage, quality and implications

DNA-based identification methods have been shown to have high detection capability and reduced costs compared to traditional methods and can also enable the detection of species that might be missed using traditional methods (e.g. rare species, cryptic species, larval stages). The success of DNA-based identification is dependent on the ‘DNA barcodes’ of target species being present in a barcode reference database. In order to use DNA-based identification methods to assess and monitor UK freshwater arthropods for biodiversity and ecological quality assessments, it is vital that comprehensive reference databases are available. Incomplete reference databases result in many sequences derived from metabarcoding not being assigned to species. Two current projects aim to create collections of high-quality sequences from expertly identified specimens of UK species. The Darwin Tree of Life project aims to sequence the genomes of all the eukaryotic species in Britain and Ireland and FreshBase aims to create a genomic reference collection for UK freshwater invertebrates. The Barcode of Life Data System (BOLD) is one of the main reference databases for animal barcodes. Prioritising the sequencing of UK freshwater arthropod species that are not yet represented in BOLD, would enable more complete identification of UK freshwater biodiversity using metabarcoding and would enable the development of primers to target specific arthropod groups or species. We analysed the coverage of UK freshwater arthropod species in BOLD. Our analyses show that coverage varies between taxonomic groups and large proportions of sequences in some orders are only represented by privately stored sequences in BOLD. Analyses of intra- and inter-specific variation in sequences stored in BOLD show that misidentifications or errors can reduce the barcode gap in some species which could cause difficulties in accurately identifying sequences derived from metabarcoding. Representation in BOLD by specimens from the UK is extremely low and analyses show that high geographic variation in sequences in some species could be important for accurate DNA-based identification of UK species. Our results have implications for prioritising the sequencing of UK freshwater arthropods and for the quality control of stored sequences in order to reduce the occurrence of misidentifications and errors that could impact the accuracy of DNA-based identification.

Diet of the black rat (Rattus rattus) in a Canary laurel forest: species identification based on morphological markers and DNA sequences

ABSTRACT The black rat (Rattus rattus) is an alien species that causes severe impact on island ecosystems, floras and faunas. The main aim of this study was to determine the plant and animal contributions to black rat diet in a pristine misty laurel forest area on La Palma (Canary Islands). Our working hypothesis was that this rat equally consumes plants and animals (fully omnivorous animal) wherever it is introduced, including pristine habitats. A total of 483 droppings collected from the terrain were first morphologically examined using a stereomicroscope, which showed high plant consumption (presence in 92.4% of droppings), followed by invertebrates (46.0%) and vertebrates (31.2%). DNA-based analyses revealed even higher proportions of plants (97%) and invertebrates (79%), while fine-scale sequence searches (DNA barcoding) in the GenBank (BLAST tool) provided a preliminary identification of 44 plants and 12 invertebrate taxa. To gain more in-depth insight into plant identification, we built up a local DNA reference collection (58 species), improving accuracy (30 species confirmed) compared to GenBank searches (25 species). Contingency analyses (chi-square and G-test) only showed significant differences in droppings between plant sequences and toxic plant presence. This study confirms that the black rat is here an omnivorous animal but with a strong plant diet component, including an intriguingly high number of toxic plants. Interestingly, despite rodents chewing on fruits and usually crushing seeds, 66 intact Rubus seeds (Rosaceae) were found in 15 droppings (3.1%). All these results suggest that black rats consume any plant types, including fruits and seeds that can be locally dispersed such as native brambles.

Revitalization of dadong dauh balinese children’s illustrated song into 2-dimensional animation as an educational tourism strategy

This study produced animated video clips revived from Balinese children’s song as an alternative media, by promoting brand equity in the form of characters and popular tourist attractions as an effort to promote cultural tourism in Bali, Indonesia. The strategy in reviving children’s songs was done through revitalizing the visualization of Balinese children’s illustrated songs. The visualization was done by turning the previous appearance of live action appearance into an animated form that proved to be preferred by children. The design of the Dadong Dauh character was constructed by manga matrix system model approach introduced by Tsukamoto. The data collection about song variation of Dadong Dauh and theory to develop imagery character and to design the character by using the manga matrix system was used by conducting a literature study. Reference collection of the visual of Dadong Dauh was used by conducting a literature study and observation. The result showed that the visualized video clip of local Balinese children songs in a two-dimensional form was able to revitalize the character branding of Dadong Dauh as a cultural symbol, with Tenganan village as its cultured environment. It also gained a great appreciation from children and has potential to popularize Dadong Dauh song.

Genomic characterization of 99 viruses from the bunyavirus families Nairoviridae, Peribunyaviridae, and Phenuiviridae, including 35 previously unsequenced viruses.

Bunyaviruses (Negarnaviricota: Bunyavirales) are a large and diverse group of viruses that include important human, veterinary, and plant pathogens. The rapid characterization of known and new emerging pathogens depends on the availability of comprehensive reference sequence databases that can be used to match unknowns, infer evolutionary relationships and pathogenic potential, and make response decisions in an evidence-based manner. In this study, we determined the coding-complete genome sequences of 99 bunyaviruses in the Centers for Disease Control and Prevention's Arbovirus Reference Collection, focusing on orthonairoviruses (family Nairoviridae), orthobunyaviruses (Peribunyaviridae), and phleboviruses (Phenuiviridae) that either completely or partially lacked genome sequences. These viruses had been collected over 66 years from 27 countries from vertebrates and arthropods representing 37 genera. Many of the viruses had been characterized serologically and through experimental infection of animals but were isolated in the pre-sequencing era. We took advantage of our unusually large sample size to systematically evaluate genomic characteristics of these viruses, including reassortment, and co-infection. We corroborated our findings using several independent molecular and virologic approaches, including Sanger sequencing of 197 genome segments, and plaque isolation of viruses from putative co-infected virus stocks. This study contributes to the described genetic diversity of bunyaviruses and will enhance the capacity to characterize emerging human pathogenic bunyaviruses.

Validation strategy of a bioinformatics whole genome sequencing workflow for Shiga toxin-producing Escherichia coli using a reference collection extensively characterized with conventional methods.

Whole genome sequencing (WGS) enables complete characterization of bacterial pathogenic isolates at single nucleotide resolution, making it the ultimate tool for routine surveillance and outbreak investigation. The lack of standardization, and the variation regarding bioinformatics workflows and parameters, however, complicates interoperability among (inter)national laboratories. We present a validation strategy applied to a bioinformatics workflow for Illumina data that performs complete characterization of Shiga toxin-producing Escherichia coli (STEC) isolates including antimicrobial resistance prediction, virulence gene detection, serotype prediction, plasmid replicon detection and sequence typing. The workflow supports three commonly used bioinformatics approaches for the detection of genes and alleles: alignment with blast+, kmer-based read mapping with KMA, and direct read mapping with SRST2. A collection of 131 STEC isolates collected from food and human sources, extensively characterized with conventional molecular methods, was used as a validation dataset. Using a validation strategy specifically adopted to WGS, we demonstrated high performance with repeatability, reproducibility, accuracy, precision, sensitivity and specificity above 95 % for the majority of all assays. The WGS workflow is publicly available as a ‘push-button’ pipeline at https://galaxy.sciensano.be. Our validation strategy and accompanying reference dataset consisting of both conventional and WGS data can be used for characterizing the performance of various bioinformatics workflows and assays, facilitating interoperability between laboratories with different WGS and bioinformatics set-ups.

Biface use in the Lower Paleolithic Levant: First insights from late Acheulean Revadim and Jaljulia (Israel)

Lower Paleolithic bifaces are one of the most ubiquitous and persistent stone tools in prehistory, proliferating from Africa through Eurasia from as early as 1.75 Mya and remaining in use for over 1.5 million years. Numerous studies have thus far focused on Acheulean handaxes’ technological characteristics, underlining their relevance in terms of early human technology, behavior and cognition. Moreover, many experimental studies have investigated the use of handaxes, highlighting their exceptional efficiency in carcass processing tasks and in other activities. However, issues of preservation have often prevented a thorough and accurate functional interpretation of Lower Paleolithic bifaces, thus limiting our current knowledge regarding their actual use. This paper presents initial results from the functional analysis of two biface assemblages originating from the Late Lower Paleolithic sites of Revadim and Jaljulia (Israel). Our analysis of use wear traces shows that handaxes at both sites appear to have been employed mainly for carcass processing. We identified differences in biface utilization at the two sites, most probably attributable to the type of animal processing activities for which these tools were employed. We also designed a dedicated experimental framework in which biface replicas were utilized in different tasks on animal, vegetal and mineral materials. This made it possible to test the efficiency of the tools and build a use-wear reference collection to which the traces observed on the archaeological specimens were compared. We thus provide a solid and reliable functional interpretation of the use of bifaces at Revadim and Jaljulia, contributing to our current understanding of the role that these tools played in the adaptation of early human groups in the Levant.

Re-Evaluation of the Podosphaera tridactyla Species Complex in Australia.

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malus prunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po. pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.

Automatic extension of corpora from the intelligent ensembling of eHealth knowledge discovery systems outputs

Corpora are one of the most valuable resources at present for building machine learning systems. However, building new corpora is an expensive task, which makes the automatic extension of corpora a highly attractive task to develop. Hence, finding new strategies that reduce the cost and effort involved in this task, while at the same time guaranteeing quality, remains an open and important challenge for the research community. In this paper, we present a set of ensembling strategies oriented toward entity and relation extraction tasks. The main goal is to combine several automatically annotated versions of corpora to produce a single version with improved quality. An ensembler is built by exploring a configuration space in search of the combination that maximizes the fitness of the ensembled collection according to a reference collection. The eHealth-KD 2019 challenge was chosen for the case study. The submitted systems’ outputs were ensembled, resulting in the construction of an automatically annotated collection of 8000 sentences. We show that using this collection as additional training input for a baseline algorithm has a positive impact on its performance. Additionally, the ensembling pipeline was used as a participant system in the 2020 edition of the challenge. The ensembled run achieved a slightly better performance than the individual runs.

Plants used in basketry production during the Early Neolithic in the north-eastern Iberian Peninsula

Plant-based artefacts are rarely preserved in archaeological contexts in the Iberian Peninsula. Very few sites with specific conditions such as waterlogging, aridity or carbonization have preserved organic material. The aim of this paper is to establish an identification criterion for identifying organic raw materials used for manufacturing plant-based artifacts by using optical microscopy. The coiled basketry remains found in La Draga (Banyoles, Girona) and Coves del Fem (Ulldemolins, Tarragona) have been studied using this method. The materials were exceptionally well-preserved by waterlogging in the case of La Draga, and carbonized or dehydrated in Coves del Fem. Samples of both coils and stitches from all the basket remains were analysed. The anatomy of their cross-sections was observed under a transmitted light bright-dark field (BF-DF) optical microscope and compared with modern reference collections. The results show the use of at least five species corresponding to four families: three monocotyledons (Poaceae, Cyperaceae and Typhaceae) and a dicotyledon (Malvaceae). Moreover, it has been possible to distinguish the part of the plant used. Variability in raw materials implied extensive environmental knowledge. Moreover, functional studies of wooden, faunal, lithic and malacological tools suggest a local production of baskets. This paper expands the current knowledge of raw materials used for basketry purposes during prehistory in the Mediterranean area as the examples from La Draga and the Coves del Fem are the oldest basketry remains that have been studied in depth in the Iberian Peninsula and Europe.

More on the identification of fish bones from southeast Arabia

AbstractIdentification of fish bones from archeological sites in southeast Arabia requires access to an extensive reference collection. This is often not possible, and repeated use of these resources when they are available ultimately damages bones. This paper provides a platform from which high‐resolution images of 60 species of marine fishes from southeast Arabia can be downloaded, aiding identification and providing illustrations that other researchers can modify to produce graphics to highlight taphonomic modification to bones or illustrate measurements taken.

An oasis soil reference collection for the identification and study of ancient cultivated soils in arid environments (Oasis of Masafi, United Arab Emirates)

AbstractOasis soils result from the combined action of natural and anthropic processes, and thus constitute valuable systems for the understanding of human–environment trajectories over the millennia. The present research aims to develop the study of ancient oasis soils by identifying proxies to detect past agricultural practices. Ten reference pits were dug in Masafi, in both cultivated plots (irrigated plots with palm trees/fruit trees/cereals; manure/ashes/carbonates) and abandoned ones. Bulk sediment samples were analysed for geochemistry/pedo‐sedimentary studies: inductively coupled plasma‐optical emission spectrometry, loss on ignition, pH, electrical conductivity, grain size and magnetic susceptibility. This multiproxy approach enabled the creation of a soil typology of oasis agricultural modes. Irrigation and liming lead to salinisation, particularly in a B‐horizon. Manure creates a hortic horizon, enriched in P and Zn. Ashes can be detected with a simultaneous increase of magnetic and salinity values. Soils in plots with fruit trees/cereals are not distinguishable from those with palm monoculture. Weathering was identified on the basis of the enrichment in Al, Ti, K Na, Ni, Cr and Fe, whereas proxies of ancient practices seem to be preserved after 15 years of abandonment. As leaching processes appear to be limited to the first 50 cm, the durability of soil signatures depends on how they were buried.

Applications of Microsatellite Markers for the Characterization of Olive Genetic Resources of Tunisia

Among the countries of the Mediterranean Basin, Tunisia is located at the crossroad for the immigration of several civilizations over the last two millennia, becoming a strategic place for gene flow, and a secondary center of diversity for olive species. Olive is one of the principal crop species in Tunisia and now it strongly characterizes the rural landscape of the country. In recent years, collecting missions on farm and in situ were carried out by various institutes, with special emphasis given to ex situ collections serving as a reference for the identification of olive germplasm. Simple Sequence Repeats (SSRs) represent the easiest and cheapest markers for olive genetic fingerprinting and have been the tool of choice for studying the genetic diversity of this crop in Tunisia, to resolve cases of homonymy and synonymy among the commercialized varieties, to identify rare cultivars, to improve knowledge about the genetic variability of this crop, to identify a hot spot of olive biodiversity in the Tunisian oasis of Degache, and to enrich the national reference collection of olive varieties. The present review describes the state of the art of the genetic characterization of the Tunisian olive germplasm and illustrate the progress obtained through the SSR markers, in individuating interesting genotypes that could be used for facing incoming problems determined by climate changes.